Journal of the SMPTE 1956-12: Vol 65 Iss 12

631

636

643

illumination Control for a Direction-indicating System
* Samuel E. Dorsey

Camera Tubes for Color TV Broadcast Service
R. G. Neuhauser

Switching and Controls for Color and Monochrome TV Studios
* James W. Thompson

Candlepower and Color Temperature of Tungsten Lamps
.* A. J. Sant aad A. J. Leta

Densitometry of en Embosseid Kinescope Recording Film
W. R. J. Brown, C. Combs and R. B. Smith

Replaceable Pole Tip. Caps for Magnetic Reproduce Heads
* Michael Rettinger

Instructions for SMPTE Registration Test Film

American Standards— 35mm Film Dimensions

This issue in Two Parts: Part 1, December 1956 Journc!; Part Il, index to Val. 65

81st SMPTE Convention + Apr. 29-May 3, 1957 +» Shoreham Hotel, Washington

65 number 12

ud

DECEMBER 1956

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JOURNAL of the
SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS

PUBLICATION OFFICE

Officers
President, 1955-56

JOHN G. FRAYNE, Westrex Corp., 6601 Romaine St., Hollywood 38, Calif.
Executive Vice-President, 1955-56

BARTON KREUZER, Radio Corporation of America, Camden, N.J.

Past President, 1955-56
HERBERT BARNETT, General Precision Equipment Corp., 92 Gold St., New York 38,
N.Y.
Engineering Vice-President, 1956-57
AXEL G. JENSEN, Bell Telephone Laboratories, Inc., Murray Hill, N.J.
Editorial Vice-President, 1955-56
NORWOOD L. SIMMONS, Eastman Kodak Co., 6706 Santa Monica Bivd.,
Hollywood 38, Calif.

Financial Vice-President, 1956-57

JOHN W. SERVIES, National Theatre Supply, 92 Gold St., New York 38, N.Y.
Convention Vice-President, 1955-56

BYRON ROUDABUSH, Byron, Inc., 1226 Wisconsin Ave., N.W., Washington, D.C.

Sections Vice-President, 1956-57
ETHAN M. STIFLE, Eastman Kodak Co., 342 Madison Ave., New York 17, N.Y.

Secretary, 1955-56
WILTON R. HOLM, E. |. du Pont de Nemours & Co., Parlin, NJ.

Treasurer, 1956-57
GEO. W. COLBURN, Geo. W. Colburn Laboratory, Inc., 164 North Wacker Dr.,
Chicago 6, Ill.
Governors, 1956-57
FRANK N. GILLETTE, General Precision Laboratory, Inc., 63 Bedford Rd..
Pleasantville, N.Y.
LORIN D. GRIGNON, Twentieth Century-Fox Film Corp., Beverly Hills, Calif.
RALPH E. LOVELL, National Broadcasting Co., 2554 Prosser Ave., '
W. Los Angeles 64, Calif.
GARLAND C. MISENER, Capital Film Laboratories, Inc., 1905 Fairview Ave., N.E.,
W ashington 2, D.C.
RICHARD O. PAINTER, General Motors Proving Ground, Milford, Mich.
REID H. RAY, Reid H. Ray Film Industries, inc., 2269 Ford Parkway, St. Paul 1, Minn.

Governors, 1955-56
GORDON A. CHAMBERS, Eastman Kodak Co., 343 State St., Rochester 4, N.Y.
JOHN W. DUVALL, E. |: du Pont de Nemours & Co., 7051 Santa Monica Bivd.,
Hollywood 38, Calif.
LLOYD T. GOLDSMITH, W arner Brothers Pictures, Inc., Burbank, Calif.
GEORGE LEWIN, Army Pictorial Center, 35-11 35 Ave., Long Island City,
W. WALLACE LOZIER, National Carbon Co., Cleveland, Ohio.
MALCOLM G, TOWNSLEY, Bell & Howell Co., 7100 McCormick Rd., Chicago 45, lil.
Governors, 1956
GEORGE H. GORDON, Eastman Kodok Co., 342 Madison Ave., New York 17, N.Y.
KENNETH M. MASON, Eastman Kodak Co., 130 E. Randolph Dr., Chicago 1, Ill.
EDWIN W. TEMPLIN, Westrex Corp., 6601 Romaine St., Hollywood 38, Calif.

Section Chairmen
BEN AKERMAN, Sto. WGST, 2646 Cheshire Bridge Rd. N.E., Atianta 5, Ga.
LEO'DINER, Leo Diner Films, 332 Golden Gate Ave., San Francisco, Calif.
ERNEST D. GAW,, Interstate Circuit, inc., 501 Chickasaw Trace, Grand Prairie,
Texas.
A. C. ROBERTSON, Eastman Kodak Co., Kodak Park Bidg. 14, Rochester 4, N.Y.
Student Chairmen
BYRL L. SIMS (USC), Dept. of Cinema, Univ. Park, Los Angeles 7, Calif.
ARNOLD FEDERBUSH (NYU), 244 West 74 St., New York, N. Y.

TWENTIETH AND NORTHAMPTON STREETS,

EASTON, PA.

Editorial Office
55 West 42d St., New York 36, New York

Editor-—VICTOR H. ALLEN

Advertising Manager—DENIS A. COURTNEY

Board of Editors

Chairman—PIERRE MERTZ,
463 West St., New York 14, New York

HARLAN L. BAUMBACH W. |. KISNER

D. MAX BEARD GLENN E. MATTHEWS
GERALD M, BEST C. DAVID MILLER
GEORGE R. CRANE JOHN A. NORLING
HAROLD E. EDGERTON HERBERT W. PANGBORN
CARLOS H. ELMER BERNARD D. PLAKUN
CHARLES R. FORDYCE R. T. VAN NIMAN
LLOYD T. GOLDSMITH JOHN H. WADDELL

LORIN D. GRIGNON
A. M. GUNDELFINGER W. C. WINTRINGHAM
DEANE R. WHITE

CHARLES W. HANDLEY
RUSSELL C. HOLSLAG CHARLES W. WYCKOFF
CLYDE R. KEITH EMERSON YORKE

Papers Committee Chairman

RALPH E. LOVELL, 2554 Prosser Ave., W. Los Angeles
64, Calif.

Subscriptions to nonmembers, $12.50 a year; single
copies, $2.00 for one-part issues, $2.50 for special
two-part issues. A 10% discount is allowed to individual
members and accredited agencies on orders for sub-
scriptions and single copies. A list of priced and gratis
publications is available. Order from the Society's
Headquarters Office, 55 West 42nd St., New York 36.

THE SOCIETY is the growth of over forty years of
achievement and leadership. Its members cre engi-
neers and technicians skilled in every branch of motion-
picture filn production and use, in television, and in the
many related arts and sciences. Through the Society
they are able to contribute effectively to the technical
advance of their industry. The Society was founded
in 1916 as the Society of Motion Picture Engineers and
was renamed in 1950.

Membership in Sustaining, Active, Associate or Student
grades is open to any interested person according to
his qualifications. in‘ormation about membership,
technical activities and standards and test films for the
industry is ava'lable from Society Headquarters.

SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS

Headquarters Office: 55 West 42d St., New York 36, N.Y. Cables: Somopict Telephone: LOngacre 5-0172

Executive Secretary: CHARLES S. STODTER

Entered as second-class matter January 15, 1930, at the Post Office at Easton, Pa., under the Act of March 3, 1879, and published monthly. —_
1957, by the Society of Motion Picture and Television Engineers, inc. Permission to republish Journal text material must be obtained in writing from the
Society’ s Headquarters Office, 55 West 42d St., New York 36. The Society is not r ible for stat ts of contributors. Printed by Mack Printing
Company, Easton, Pa.

“ee
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VOLUME 65 +

Illumination Control for a Direction-Indicating
System for the M-45 Tracking Camera Mount

A powered tracking mount for rocket and guided missile photography has been
developed at the U.S. Naval Ordnance Test Station, China Lake, Calif., as pre-
viously described in this Journal.' This mount, designated as the M-45 ‘‘Gooney-
Bird,’’ has now been further improved through the addition of direction- indicat-
ing equipment. The design and development of an electronic illumination control
for this direction-indicating and recording system are described in this article.

‘y= PRINCIPAL parts of the direction-
indicating system for the M-45 tracking
camera are shown in block form in Fig.
1. The Mitchell chronograph camera in
the M-45 has a small side lens and mir-
ror combination which is used to photo-
graph a secondary image in one corner
of the film frame simultaneously with
the recording of the main image. This
side lens was originally used to photo-
graph the dial of a stopwatch to give the
time the image was taken, but the stop-
watch method was not as accurate as

A contribution received on October 16, 1956,
from Samuel E. Dorsey, Research Dept., U.S.
Naval Ordnance Test Station, China Lake, Calif.

1 Myron A. Bondelid, “The M-45 Tracking
Mount,” Jour. SMPTE, 61; 175-182, Aug. 1953.

YNCHRO

SYNCHRO

DIALS DIALS

desired and did not lend itself to syn-
chronization with other instrumentation.
Timing information is now provided by
the recording of binary coded timing
markers along one side of the film.

Figure 2 is an artist’s drawing of a
frame of film shot by the Mitchell
chronograph camera in the improved
M-45. The side lens image of the direc-
tion-indicator dials can be seen in one
corner of each frame. The binary coded
timing markers are not included in this
sketch.

Two synchro generators are situated
in the angular-positioning gears of the
M-45 — one to gather information of
azimuth; and the other, information on
elevation. The gears are such that the

OK OPERATED UNIT
CONTACTS

ELECTRONIC

é,

Fig. 1. System block diagram.

MITCHE.L CHRONOGRAPH CAMERA

NUMBER 12 +

DECEMBER 1956

By SAMUEL E. DORSEY

shafts of the generators rotate 36 times as
fast as the camera mount, or one revolu-
tion for each 10 degrees of rotation of the
mount. This information is transmitted
to two synchro motors mounted within an
enclosure attached to the side lens of the
Mitchell chronograph camera. Each
synchro motor has two dials, one of which
it drives directly and the other, much
more slowly, by gears. These four dials
can be photographed; however, if the
dials were constantly illuminated while
the camera mount rotated, there would
be enough movement of the dials when
the shutter was open to smear the read-
ings and make them useless. To eliminate
this smear, the dials are illuminated by

‘flash lamps. These lamps operate through

the flashlamp control unit by means of
the shutter-controlled contacts within
the Mitchell chronograph camera.

Fig. 2. Film sample.

December 1956 Journal ofthe SMPTE Volume 65

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and Television Engineers
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Fig. 3. Synchro motor-driven dials.

Fig. 4. Camera with dial box in place.

Fig. 5. Camera, dial box, and flashlamp control chassis interconnected.

Figure 3 illustrates the synchro motor-
driven dials. In Fig. 4, the camera is
mounted with its side lens dial box at-
tachment in place. Figure 5 shows the
camera, dial box, and the flashlamp
control chassis interconnected (the entire
system with which this article is con-
cerned except for the synchro generators).
Figure 6 shows the improved M-45 in
operation on one of the ranges at the
U.S. Naval Ordnance Test Station,
China Lake.

The Electronic System

The shutter-operated contacts in the
chronograph camera and the flashlamp
control unit furnish power and syn-
chronization to the flash lamps so that

their flashes illuminate the synchro-
operated dials at the instant the camera
shutter is wide open to the side lens.

The electronic flashlamp control is
shown in block diagram (Fig. 7). In
order to flash the lamps properly, two
difficulties had to be overcome:

(7) The system was made more insensi-
tive to chatter, as follows (refer to block
diagram, Fig. 7, and the exaggerated
and idealized waveforms in Fig. 8): As
long as the shutter-operated contacts are
closed, the input (a) from the contacts is
grounded and, therefore, has zero voltage.
When the contacts open, the voltage
very quickly rises to approximately 100 v
through the resistor R1. Thus the wave-

form of voltage in Fig. 8(a) has an al-
most instantaneous rise at the moment
the contacts break clean, and a chatter
appears at the time the contacts are
closed. The output (b) of the first RC
differentiator is fed into the signal input
of the gating amplifier-inverter. The
output (c) of this amplifier is fed back
through a loop, consisting of a one-shot
multivibrator and an RC delay circuit,
into the control input of the gating
amplifier. As it is a single-stage ampli-
fier, it also inverts the signal it passes.
Thus, a positive pulse obtained at (b)
through differentiation of the wave front
at (a) appears as a negative pulse at (c).

When the one-shot multivibrator re-
ceives a negative pulse at the input, it
injects into its output another negative
pulse much longer than the input pulse.
The one-shot multivibrator allows the
first pulse of a camera-shutter cycle to
pass through the gating amplifier to (c),
but closes the gate and holds it closed at
the time the chatter, which contains
positive pulses due to differentiation,
appears at the signal input of the gate.

The RC delay slows the action of the
gate control by the one-shot multivi-
brator so that it does not take effect until
the first pulse passes. The length of the
pulse out of the one-shot multivibrator
must be greater than that shown in
Fig. 8 (e-1), long enough to blot out the
chatter but not so long that it interferes
with the passage of the first pulse of the
next camera-shutter cycle. In fact, the
multivibrator must be ready to trip
again at the onset of each succeeding
shutter cycle. This maximum pulse length
(6 or 10 msec—depending on the
speed of the camera) is shown approxi-
mately in Fig. 8 (e-2).

The exact delay time to incorporate
into the multivibrator was determined
by the use of the graph in Fig. 9. Its
horizontal axis represents the speed of
the camera and, therefore, the fre-
quency of the input pulses from its con-
tacts. The vertical axis represents the de-
lay time of the multivibrator. The upper
diagonal represents the repetition time
of the input signal, while the lower
diagonal represents the width of the
input pulse. Attempted operation above
the upper limit would cause the multi-
vibrator pulses to be too long for the
repetition rate indicated and interfere
with subsequent input pulses. Attempted
operation below the lower limit would
cause the multivibrator output pulses to
be so short in comparison with the input
pulse that the multivibrator pulse would
be completed before the occurrence of
the chatter and wouid give no protection.
Thus, only the area between the diag-
onals is effective.

A delay of 8 msec is in the effective
region for all desired speeds; but since
the upper and lower limits are very close
to erratic operation, two ranges are
used. A switch on ‘he front of the chassis

632 December 1956 Journal of the SMPTE Volume 65

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chooses either 6 or 10 msec by changing
capacitor values in the multivibrator
circuit. These two positions (6 or 10
msec) are labeled “over 70 fps” and
“under 30 fps” (flashes per second) and
are used when the camera speeds are at
these rates. When the camera speed is
between these two extreme values, either
switch position may be used.

(2) To overcome the difficulty of re-
quiring 120 flashes/sec (the maximum
speed required of the camera being 120
frames/sec) of lamps rated only 100
flashes/sec, two lamps were used and
they were flashed alternately (see Figs.
7 and 10).

To accomplish this, the negative
output pulses of the gate (c) are fed into
a binary flip-flop. Both output circuits
of the flip-flop are employed, each feed-
ing an RC differentiator with square
waves oppositely phased and of half the

ist RC
DIFFERENTIATOR

SIGNAL INPUT

+100V

SHUTTER OPERATED
CONTACTS

| BINARY FLIP-FLOP
OuUTPUT A

| RC
DIFFERENTIAT

4
GATING ae ONE - SHOT
re RC DELAY MULTIVIBRATOR
I

GGER
(@)
A A A

Powe R
SUPPLY

| PARK im) |
Bed Re | THYR ATRON
Lame CAPAC IT
DIFFERENTIATOR TRIGGER

Fig. 7. Block diagram of flashlamp control.

INSTANT OF FLASH

ue INSTANT OF FLASH

= ~ INSTANT OF FLASH

~ INSTANT OF FLASH

a

|

Fig. 8. Idealized waveforms.

(a) SIGNAL FROM CONTACTS

OUTPUT OF Ist
DIFFERENTIATOR

©) GATING

(d-1) SHORTEST OUTPUT OF
ONE-SHOT MULTIVIBRATOR

(4-2) LONGEST OUTPUT OF
ONE-SHOT MULTIVIBRATOR

(e-!) OUTPUT OF RC DELAY WITH
SHORTEST TIME OF MULTIVIBRATOR

(e-2) OUTPUT OF RC DELAY WITH
LONGEST TIME OF MULTIVIBRATOR

Illumination Control for a Direction-Indicating System

Fig. 6. M-45 tracking camera mount.

frequency of the gate output, Fig. 10 (c),
(f) and (g). The pulses resulting from
this differentiation of the output of the
flip-flop, shown in Fig. 10 (h) and (i),
are fed into cathode followers which act
as buffers. The grid of each cathode
follower is rather heavily biased so that
the outputs contain only the positive
parts of (h) and (i). These are shown in
(j) and (k) of Fig. 10 as positive pulses at
half the frequency of the camera cycle and
are 180° out of phase with each other.
Each buffer drives a thyratron, its out-
put pulse causing the thyratron to dis-
charge a capacitor into the primary of a
spark coil. The discharge into the spark
coil causes its secondary to trigger the
flashing of the proper flashlamp, as
shown in Fig. 10 (1) and (m). The flash-
lamp, upon being triggered, causes its
flash capacitor to discharge suddenly
through the lamp and produce a flash
of light. The thyratrons and the flash-
lamps are self-extinguishing and so are
ready for succeeding cycles.

The circuit diagram of the electronic
flash-control unit is given in Fig. 11.
The Power Supply and Plug-In Units
are shown in Figs. 12 and 13.

Conclusion

Position data from the M-45 opens
up a whole new field of use for the mount.
Because of its mobility, the M-45 can
service any range and make position
data available to it.

633

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INSTANT OF FLASH
INSTANT OF FLASH

INSTANT OF FLASH

|

REF

ail INSTANT OF FLASH

(Cc) OUTPUT OF
GATING AMPLIFIER

| (f) OUTPUT "AY OF

REF BINARY FLIP-FLOP

(F OUTPUT *B" OF
BINARY FLIP-FLOP

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SPEED

8910

GiENT SPEED

E

\. (h) OUTPUT OF 2nd RC

REF DIFFERENTIATOR

T (MILLISECONDS)

ION OF

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(1) OUTPUT OF Brd RC

REF DIFFERENTIATOR

(J) OUTPUT OF
BUFFER

(k) OUTPUT OF

40 50 & 70 80 90 100
N(RPS) REF (m) FLASH LAMP “B"

Fig. 9. Choice of multivibrator time. Fig. 10. Idealized waveforms.

NOTE:
1. EXCEPT AS NOTED: ALL CAPACI-
TORS IN wf. +S. ALL RESISTORS | WATT,
2 WITH MULTIVIBRATOR PIN® 7
CONNECTED TO -!5SOV SUPPLY.
3S. OIFFERENT VALVES OS8TAINED BY
MOMENTARY GROUNDING PIN
oR 11 OF BINARY COUNTER,
+ WITH 2021'S OUT OF SOCKETS.

Fig. 11. Circuit diagram of electronic flash control unit.

634 December 1956 Journal ofthe SMPTE Volume 65

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SWITCH POSITION
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Fig. 12. Power supply for electronic flash control unit.

BINARY COUNTER DELAY MULTIVIBRATOR GATE
NOTS PLUG-IN UNIT NOTS PLUG-IN UNIT NOTS PLUG-IN UNIT
TYPE | TYPE 2 TYPE 16

Fig. 13. Plug-in units used in electronic flash control.

Illumination Control for a Direction-Indicating System

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Dorsey: 635

Camera Tubes for

Color Television Broadcast Service

A brief review is made of tubes currently used in television camera systems and of
tubes which have been found basically unsuitable for color camera work. General
requirements of tubes for color television pickup are discussed, and basic perform-
ance characteristics that limit the pickup field to several tubes for color television are
evaluated. The performance characteristics of vidicons and image orthicons now
used are compared with the required characteristics. Quality problems encoun-
tered in color pickup are discussed, and methods used to overcome these problems
are described. Operating devices used to improve performance are evaluated.

4 DIFFERENT Camera tubes are used
in color cameras for television broadcast-
ing: the vidicon and the image orthicon.
At present, these are the only tubes that
have been found useful for producing an
acceptable color picture under the re-
quirements imposed by broadcast stand-
ards and practices. Each of these tubes
has desirable characteristics that make
it suitable for particular conditions or
applications. Neither tube at the present
time is fully capable of being used for all
broadcast applications. Therefore, the
two tubes are used in different manners
and for different service. The image
orthicon is used in cameras for both
studio and outdoor live pickup. The
vidicon is used in film and slide pickup
service or in live scenes for which high
light-levels can be conveniently pro-

Presented on October 8, 1956, at the Society’s
Convention at Los Angeles by R. G. Neuhauser,
Tube Div., Radio Corp. of America, Lancaster,
Pa.

(This paper was received on October 17, 1956.)

LENS

RELAY

BLUE -REFLECTING —
DICHROIC MIRROR

FRONT
SURFACE
MIRROR
NEUTRAL -
DENSITY
FILTER

BLUE FILTER

GREEN
FILTER

BLUE GREEN REO
Fig. 1. Block diagram of color television camera optical

system using three image orthicons.

INFRA-RED
FILTER

— IRIS

— RED - REFLECTING
DICHROIC MIRROR

RED FILTER

FRONT
SURFACE
MIRROR

duced. In both cases, the tubes are op-
erated in a simultaneous camera system
employing three tubes to produce the
required information for the formulation
of a color television signal.

The type of layout and optical system
utilized for the two different cameras is
slightly different, although the cameras
have the same general layout and ar-
rangements for light splitting and optical
registry. A block diagram of each of the
systems is shown in Figs. 1 and 2. In both
of the systems, the primary image is
focused on the plane of a condenser lens
and relayed to the tube face upon which
the proper color image is formed. This
system is utilized to provide a suitable
working distance between the lens of the
camera or film projector and the tube
faces for the light-splitting elements of
the optical system. Each system is unique
in its application.

Because live camera requirements are
such that different lenses are required for
different angle shots, it is desirable to

— OBJECTIVE
LENS

CONDENSER LENS

PARTIALLY
SILVERED
MIRROR

BLUE REFLECTING
DICHROIC

FRONT
SURFACE
MIRROR

By R. G. NEUHAUSER

change only one objective lens for this
purpose. In the film camera system, it is
advantageous to project several different
images into the system in succession from
different projectors. The objective lenses
of the three color channels remain fixed
in this case, and the different images are
projected onto the plane of the condenser
lens by an optical multiplexing system.

The video signals that are derived from
the three camera tubes of the color
camera, when ontical images are prop-
erly registered on the tube faces and the
camera tubes are scanned in proper
registration, represent the red, blue and
green information of each portion of the
scene. These signals are used to form the
final color signal. Each video signal rep-
resents a sharply defined image of the
red, blue or green information of the
original scene.

Performance Specifications
for Color Camera Tubes

Numerous specifications might be de-
vised for performance and electrical
characteristics of camera tubes for both
simultaneous and sequential color tele-
vision cameras. The most important
characteristics determining directly the
accuracy of reproduction of a color scene
are:

Sensitivity
Light-Transfer Characteristics
Black-Level Reproduction

OR SLIDE

PROJECTION LENS

——+——- FOCUS PLANE OF
FILM IMAGE

FRONT
SURFACE
MIRROR

|

NEUTRAL-
DENSITY
FILTER CAMERA LENSES
WITH IRIS
AND FOCUS
MECHANISMS

—=—-|MAGE

ORTHICONS

BLUE
CHANNEL
Fig. 2. Block diagram of color television camera optical system
using three vidicons.

IDENTICAL—= <>

TRIMMING
FILTERS

VIDICONS

REO GREEN
CHANNEL CHANNEL

636 December 1956 Journal of the SMPTE Volume 65

v
4
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Spectral Response

Resolution and Ability to Register
Images

Signal-to-Noise Ratio

A review of each one of the above
characteristics follows to illustrate its
importance and significance in color
television camera use.

Sensitivity: The photosensitivity of the
tube for direct studio pickup should be
very high because of light loss and ab-
sorption in the optical and color trimming
system. The lens system should pick up
and transfer to the camera tubes enough
light to properly expose the three tubes.
Studio lighting requirements become al-
most prohibitive if more than 500 ft-c
are required. Depth of focus should be
equivalent to that provided on double-
frame 35mm film with an aperture of
not less than //6.3.

Film pickup requirements are less
stringent, since it is easy to obtain aver-
age illumination levels of 0.5 to 1.0 lumen
on the photosensitive surface of the cam-
era tube from the film projector. Sensi-
tivity is no problem for a camera tube
for this application, provided the tube
can store the information during film
pulldown time.

Light-Transfer Characteristics: A camera
tube for color pickup should have a pre-
dictable and constant light input vs.
signal output that is the exact comple-
ment of the grid-drive vs. light-output
characteristic of the reproducing kine-
scope. The desired characteristic is a
signal output that varies approximately as
the 1/2.5 power of the incident illumina-
tion or, in television tube terminology,
a constant “gamma” of 0.4. By the use of
appropriate gamma-correction circuits
in the video amplifier, a video signal
having practically any transfer charac-
teristic can be modified to produce a
signal having the desired signal gradient.
It is preferable, but not a requisite, that
this characteristic follow a simple power
law for the values of illumination to sim-
plify the gamma-correction circuits.

predictable gamma_ characteristic
is desired so that each portion of the video
signal developed has an exact relationship
to the light energy of the scene that
reaches the corresponding portion of the
camera tube. The signal should not be
affected by overall illumination level or
adjacent area illumination or other
modifying influences. If these conditions
are not met, colors of different luminosity
will not be reproduced in proper hue,
and portions of a scene will have their
hue or saturation change as a function of
the overall illumination level or illumina-
tion of adjacent portions of the scene.

Black-Level Reproduction: This charac-
teristic is usually considered as a separate
one for a camera tube. If the requirement

Neuhauser:

of predictable gamma is achieved, ac-
curate black-level will automatically re-
sult. Conversely, any tube that does not
produce a signal having substantially
accurate black-level information will not
be suitable for simultaneous color camera
operation. Small values of spurious signal
developed during scan can usually be
compensated by “shading” insertion if
they do not change with scene illumina-
iion.

Spectral Response: Contrary to what
might at first be assumed, exact duplica-
tion of a particular spectral response is
not necessary from tube to tube. Spectral
response curves of photosensitive devices
do not usually show abrupt discontinui-
ties. A reasonable photosensitivity over
the entire visible spectrum is, therefore,
the only special requirement because the
shape of the spectral “taking”? charac-
teristic of each color channel can be and
is controlled primarily by the light-
splitting and color filter portions of the
camera optical system, and the amount
of light transferred to each tube is con-
trolled to compensate for its response in
the particular color channel in which it is
operating. Indeed, each tube in the sys-
tem need only have photoresponse to the
light in its particular colorbands. For
practical purposes, however, it is desir-
able that one type of tube be usable in
any of the three color channels. The rela-
tive response to each portion of the spec-
trum is rather unimportant, since bal-
ance can be easily achieved by gain con-
trol or by individual color optical-chan-
ne! light control by means of neutral-
density-filter changes or changes in effec-
tive sensitivity of the camera tubes.
These controls are needed to compensate
for the differences in the overall photo-
sensitivities of camera tubes that are a
normal result of the processing of the
photosensitive surface.

Resolution and Ability to Register Images:
Resolving requirements of a camera tube
for color operation are much the same as
those of a black-and-white system. It is
desirable to have good response to all
detail information that can be trans-
mitted within the video channel. A sec-
ond factor not directly related to the tube
resolving capabilities, but affecting the
resolution of the final color picture, is the
ability to register images in both the
optical and the time-position sense that is
imposed by the television scanning
process. Tube geometry, optical image
similarity, and deflection methods and
equipment should be precise enough to
enable the camera to produce three
images that are well registered.

Inherent geometric distortions of any
of these processes or parts (optical, tube
performance, and deflection components
and system) are of themselves not impor-
tant, but variations in any one of these
factors from channel to channel can pro-

duce misregistration and a resulting loss
of resolution.

Signal-to-Noise Ratio: High signal-to-
noise ratios of the video signal developed
by the camera tubes are essential. The
requirements are probably more stringent
for color than black-and-white, since
there is some evidence that high-fre-
quency noise beating against the color
subcarrier produces low-frequency noise
which is more objectionable visibly than
high-frequency noise. Signal-to-noise
ratios of the individual color channels
should be at least 60 to 1 for good black-
and-white reproduction of the color
signal. Operations on the video signal,
such as gamma correction and aperture
correction, usually decrease the signal-
to-noise ratios. This decrease is partially
off-set by the fact that the luminance-
channel signal is derived by the addition
of signals from three color channels; the
signals add directly while the noise adds
in quadrature, resulting in a better sig-
nal-to-noise ratio of the luminance
channel than is present in any of the
color channels.

Specifications Applied
to Available Camera Tubes

Comparison of available camera tubes
with these specifications shows certain
discrepancies:

High-Velocity Scanning Tubes: Camera
tubes employing high-velocity scanning
at present do not meet the specification
given above for predictable light-transfer
characteristics or proper black-level
reproduction. The uncontrolled second-
ary electrons generated and redistrib-
uted in the high-velocity scanning proc-
ess distort somewhat the tone rendition of
adjacent areas and create spurious sig-
nals that are a function of illumination
levels and scene content. Tubes employ-
ing high-velocity scanning are the image
iconoscope and the iconoscope.

Low-Sensitivity Tubes: Tubes such as
the image dissector might be considered
‘or color television pickup except for
their lack of sensitivity. Also, their in-
ability to store information makes neces-
sary constant illumination during pic-
ture scanning time.

The CPS Emitron or orthicon-type
tube is a medium-sensitivity tube requir-
ing four to five times the light required
by the image orthicon, making it, at the
present time, a marginal performer for
simultaneous color pickup. Otherwise, it
meets most of the other requirements of a
tube for this service. The dynamic con-
trast range of this tube is rather re-
stricted since it is a linear transducer of
light. Consequently it has not given
satisfactory performance in film pickup
service due to the wide dynamic light
range encountered in film.

Camera Tubes for Color TV Broadcast Service 637

a

i

| {
|
|
|

SCENE = SMALL-AREA HIGHLIGHT ON DARK BACKGROUND

RCA 6474/1854

4

7
i

RCA- 5820

TARGET - MESH

SPACING =.0025

TYPICAL SIGNAL OUTPUT-MICROAMPERES

0.001

a

0.01 0.1
HIGHLIGHT ILLUMINATION ON PHOTOCATHODE - FOOT-CANOLES

4 6 2
1.0

Fig. 3. Light transfer characteristics of image orthicon RCA-6474/1854 for color pickup

and RCA-5820 for black-and-white pickup.

Image Orthicon as a Color Camera Tube

The image orthicon, as designed and
operated for color pickup, meets all of
the basic requirements for a camera tube
for simultaneous color pickup, although
it meets some requirements with greater
ease than others. Operation under the
**knee,”’ i.e. limiting the highlights of the
scene by iris or lighting control to the
relatively linear initial portion of the
curve of Fig. 3, produces a predictable
light transfer characteristic that is essen-
tially linear. Operation so that the high-
lights of the scene are over the knee por-
tion of the curve is undesirable because,
in this instance, the image section
behaves in a manner similar to a tube
operated with high-velocity scanning.
The secondary electrons from the target
are then no longer collected by the tar-
get collector mesh but are free to travel
some distance from their point of origin
and, upon landing, distort adjacent area
charge patterns, with a resulting loss of
accurate black-level at these points, or
distortion of other tonal values.

For example, a human face has fairly
high red light reflectivity. If the camera
were operated so that the illumination
of the red camera tube only was “over
the knee,” two things would happen.
First, the facial tones would turn toward
the blue-green because the output of the
red tube would be limited in the facial
highlights. ‘This loss of red signal would
be partially represented as electron charge
redistribution to the darker surroundings.
The second effect, therefore, would be to
drive the adjacent low-light areas of the
red scene toward black level, producing
blue or blue-green shadows due to a
deficiency of red signal from these areas.
This effect would take place in either

638 December 1956 Journal of the SMPTE

sequential or simultaneous color cameras,
if operated in this manner. Image-orthi-
con tubes designed for color have a high-
capacitance target-mesh assembly made
possible by spacing the target and mesh
0.001 in. This close spacing extends the
linear portion of the curve under the
knee and thereby improves the signal-
to-noise and contrast range.

The sensitivity of the image orthicon is
higher than that of any competing camera
tube. When properly exposed, excluding
the light loss due to color filters in a
color system, the image orthicon itself as
used for color cameras is as sensitive as a
photographic film having an ASA speed
index of 500. This comparison is valid if
the “shutter”? speed is considered to be
equal to that of the television frame rate.

The spectral response curve of the
image orthicon, as shown in Fig. 4, illus-
trates that it has a considerable response
in all portions of the visible spectrum; in
fact, it has a wider response than the eye.

It might be well to bring up a signifi-
cant point at this time with respect to
the camera tube exposures and sensitivi-
ties. The color system is required to
reproduce all portions of the scene that
would be seen by the human eye, i.e.,
all information between approximately
4000 and 7000 A radiation; but it must
reproduce it as it exists, not as it appears
to the eye. Therefore, for equal energy
(white card, etc.) each camera tube
should produce the same signal output.
An examination of the spectral sensi-
tivity curves shows that, even if identical
color-filter efficiency is assumed, equal
signals would not be produced when the
tubes are operated in a color camera.
Therefore a balance of illumination levels
of each channel of the color cameras is

required to produce equal signals. (Elec-
trical amplification could do the same,
but signal-to-noise ratio of the under-
exposed channels would be unsatisfac-
tory.)

In general, the red and blue channels
have lower sensitivity than the green
channel. When the image orthicon is
used with incandescent light, the red and
blue channels have about the same sensi-
tivity, while the green channel usually
receives more than enough light for the
required exposure unless padded down
by neutral density filters.

Black Level: The image orthicon is
capable of producing a signal propor-
tional to illumination, as illustrated in
the discussion of transfer characteristics.
Therefore, it is inherently capable of pro-
ducing a good black-level signal during
retrace that is representative of true
blacks in the scene. Certain tube effects
produce some deviation from true black-
level, but these effects are not a function
of scene illumination or camera expo-
sure. They are termed “shading” signals
caused by incomplete or improper col-
lection of the return beam and _ they
appear as a stationary pattern. Secondly,
since the return beam is partially in focus
as it strikes the first dynode, the dynode
surface texture may be evident in dark
areas of a scene. The larger components
of this spurious signal can be compen-
sated for by the addition of a fixed
amount of shading signal to the video
signals, but the dynode surface texture
remains to contribute black-level error or
unwanted signal.

Resolution: The resolving characteris-
tics of the image orthicon tube have been
found to be fully adequate for black-and-
white broadcast television with present
standards. The same degree of adequacy
should apply to the image orthicon as
used for color broadcast transmission.
Registration errors contribute to loss of
effective resolution, necessitating correc-
tive measures, such as aperture correc-
tion of the individual color channel sig-
nals or of the luminance component of
the color signal, to improve the resolving
capabilities of the signal.

The number usually associated with
the resolution capabilities of the image
orthicon does not tell the whole story.
The pictures deve!oped by an image
orthicon as operated for color and as
operated for black-and-white television
are sufficiently different in appearance
to warrant some examination of the
nature of this difference and its effect on
apparent sharpness. The difference, of
course, lies in “over-the-knee” operation
as used in black-and-white cameras
versus “under-the-knee’” operation in
color cameras.

The knee characteristic of an image
orthicon is a result of the storage surface
charging up to a potential at which fur-

Volume 65

6
2 6 2
|

T T T T |
Fr TEST PATTERN: SQUARE WAVE
| DASHED CURVE SHOWS SPECTRAL CHAR- + RESPONSE MEASURED IN. SYSTEM
ACTERISTIC OF AVERAGE HUMAN EYE HAVING I0-Mc BANDWIOTH
120}— HIGHLIGHTS IN RELATION
aoe CURVE| TO LIGHT TRANSFER
<> CHARACTERISTIC
co1}— 208 ABOVE KNEE
«
ae \ Eg
w
2a < ae
‘
~
= jo & ae
2000 4000 6000 8000 —
WAVELENGTH —ANGSTROMS
45 <
g22 35 w Sa
az TELEVISION LINE NUMBER
Fig. 4. Spectral sensitivity characteristic of image orthicon Fig. 5. Amplitude response characteristics of image orthicon.

ther voltage buildup is limited by re-
turning secondary electrons. In_ this
process two things happen that modify
the apparent resolving capabilities of the
tube.

The first is illustrated by the amplitude
response curves of the image orthicon as
shown on Fig. 5. Here, the curve for
operation ‘‘one stop over the knee” shows
an increase in detai! information re-
sponse above a certain point. The ex-
planation lies in the fact that small
areas, or edges of large areas, have an
effectively higher capacitance per unit
area than large areas have. This differ-
ence is due to the added capacitance of
the differently charged adjacent areas on
the target glass. (For large areas, the ca-
pacitance is essentially only parallel plate
capacitance between target glass and
mesh.) These small areas and edges ac-
cumulate a greater charge before being
voltage limited by redistributed elec-
trons and, therefore, produce an effec-
tively higher signal, resulting in an ap-
parently sharper image. This action
enhances the contrast of small area
signals and the outline or boundary of
large area signals.

A second factor contributing to the ap-
parently greater resolution of the image
orthicon operated over the knee in
black-and-white service is the redistribu-
tion to the adjacent areas of low-ve-
locity electrons produced at a highlight.
These low-velocity electrons discharge
the adjacent areas causing enhanced
contrast. This enhanced contrast is not
unlike halation that is produced in a
kinescope by internal light reflection
within the faceplate, but is negative in
the sense that it is a “black’’ halo instead
of a “white” halo. In effect, the image
orthicon operated in this manner is in-
herently capable of developing a signal
that tends to cancel or compensate for the

halations normally produced in a kine-
scope.

The signal-to-noise ratio of the signal
produced by the close-spaced image
orthicon used in color television is ap-
proximately 70 to 1 (peak signal to rms
noise). When the color signals are added
in the colorplexer in the proper propor-
tions, the noise currents add in quadra-
ture, while the signals add directly, giving
an inherent improvement in signal-to-
noise ratio. However, the necessary
gamma correction and aperture correc-
tion of the signals both tend to decrease
the signal-to-noise ratio. It is, therefore,
difficult to assign a number to the signal-
to-noise ratio of the color signal de-
veloped by a camera using image orthi-
cons. The noise is below the objection-
able point but has little reserve and,
therefore, requires that careful attention

be given to those operating factors that
will maintain the best signal-to-noise
ratio. These factors include the use of
minimum beam current, proper multi-
plier focus settings, and proper amounts
of aperture correction and target voltage
setup.

Vidicon as a Color Camera Tube

The vidicon as a color camera tube
meets all but one of the requirements for
a universal color camera tube. The limi-
tation of present vidicon tubes in com-
parison with the image orthicon is sen-
sitivity. The sensitivity results in the
vidicon being used primarily for film
pickup work or direct pickup in areas
having very high light levels and re-
stricted speed of motion. The speed of |
response of the present photoconductor
varies with the illumination level, mak-

ILLUMINATION: UNIFORM OVER PHOTOCONDUCTIVE LAYER
1.0 SCANNED AREA OF PHOTOCONDUCTIVE LAYER=1/2 x 3/8
“Bt Ems=SIGNAL -ELECTRODE VOLTS TO GIVE MAX. SENSI—
6 TIVITY AT MAX. DARK CURRENT OF 0.02 MICROAMP.
4
3
= 2
S >
= 4 Zz
3
a
3 001 ‘ ‘Ca
8 - +
=
4
3
0.001
0.01 0.1 1.0 10 100 1000
2870°K TUNGSTEN ILLUMINATION ON TUBE FACE—FOOT-CANDLES
92CM-9086
Fig. 6. Light-transfer characteristics of vidicon.
Neuhauser: Camera Tubes for Color TV Broadcast Service 639

t
|
|

8

FOR EQUAL VALUES OF
RADIANT FLUX AT
ALL WAVELENGTHS

RELATIVE RESPONSE — PER CENT
8

5000 7000
WAVELENGTH — ANGSTROMS

Fig. 7. Spectral sensitivity characteristics of vidicon.

ing it not very useful for conventional
sequential-type of color pickup. The lag
or carry-over of signal from one field to
another has generally been found to pro-
duce objectionable color dilution under
all but the highest light levels when used
in a sequential camera in other than
color broadcast applications. The sen-
sitivity of the vidicon itself, as operated
for direct pickup applications to produce
desirable lag characteristics, corresponds
to that of photographic film having an
ASA speed index of no more than 5.
For film pickup, where light is no
problem, the vidicon meets the outlined
specifications for color pickup very well.
The light transfer characteristics of the
vidicon are the most precise of any
camera tube. Besides being extremely
predictable and unaffected by scene con-

tent, the transfer characteristic is nearly
ideally suited to compensate for that of
the reproducing kinescope. The shape
of the light transfer characteristics, as
shown on Fig. 6, is almost entirely de-
pendent upon the photoconductive ma-
terial properties and has proven to be
constant from tube to tube. The low-
velocity scanning process produces no
secondary electrons that can escape to
adjacent areas and cause image-charge
distortion.

Black-level is also very predictable
and constant. As operated for film pick-
up, black represents essentially zero signal
current and is, therefore, constant at all
parts of the tube in the absence of light.
In this respect it also excells any other
camera tube.

The spectral response of the vidicon

qT

BANDWIDTH

HIGHLIGHT SIGNAL-ELECTRODE MICROAMPERES =0.35

TEST PATTERN: TRANSPARENT SQUARE - WAVE
RESOLUTION WEDGE

[| Mc = 8O TV LINES (APPROX.)

4.5Mc BROADCAST

| q

AMPLITUDE RESPONSE —
ARBITRARY UNITS

200

400
TV LINE NUMBER

600 800

Fig. 8. Amplitude response characteristics of vidicon showing effect of aperture correc-
tion on horizontal amplitude response of vidicon.

(Fig. 7) illustrates its adequate response
in all portions of the visible spectrum.
Its response in the red regions is slightly
lower than desired but has not been a
problem, especially with projectors using
incandescent light.

An operating convenience is present
in the fact that the light levels into each
tube do not have to be balanced as pre-
cisely as in the image-orthicon camera,
because the light transfer characteristics
have no knee or discontinuity of slope.
Consequently camera setup is relatively
simple because, within limits, the signal
outputs can be balanced by signal elec-
trode voltage control.

The resolution of the vidicon has
proven very adequate for both color and
black-and-white film pickup, especially
when appropriate aperture correction is
used. The curves of Fig. 8 show the re-
sponse of the tube with and without
aperture compensation. Full modulation
in the broadcast channel in the horizon-
tal direction is obtainable as shown, al-
though the effective modulation is
slightly less because of the single-dimen-
sion correction process used. Although
its uncompensated response is somewhat
lower than that of some camera tubes, it
does have response at very high line
numbers. Secondly, the high signal-to-
noise ratio of the video signal allows cor-
rective measures to be taken and still
maintain an excellent signal-to-noise
ratio.

Due to its simple construction and
geometry, there is inherently little geo-
metric distortion of the images within
the tube. This feature makes registration
over the entire raster very easy and pre-
cise and, therefore, maintains the good
resolving capabilities of the tube.

These foregoing features permit rela-
tively uncritical operation of the camera
without departure from good color pic-
ture quality.

The signal-to-noise ratio of the vidicon
can be as high as 300 to 1. Aperture cor-
rection reduces this ratio to approxi-
mately 100 to 1. Because only a small
amount of additional gamma correction
is needed for film having a wide con-
trast range, little additionz’ noise is
added in this process in conmiparison to
gamma correction for other camera
tubes or devices. The vidicon color signal
is, therefore, essentially noise free even
when operated with dense film stock and
remains constant since light is used to
compensate for different film-stock trans-
mission.

All of these positive features concern-
ing vidicon operation in this service lead
one to assume, and rightly so, that the
vidicon-type tube is the camera tube
“most likely to succeed.”” There is a
theoretical limit to the possible vidicon
sensitivity which is many times that of
the present tube. A small portion of this
possible increase would amply satisfy all
of the sensitivity needs of a camera tube

640 December 1956 Journal ofthe SMPTE Volume 65

|
|
|
\
4
‘
I>
4
4,
Xs,

for the forseeable future. Indeed, with
such a sensitivity available, the quantum
nature of light would provide the ultimate
limitation on transmitted picture quality.

Difficulties in Three-Tube Systems

No system that is as complex as a three-
tube color television system is free of
difficulties. Some of these difficulties are
rather basic; others are either quality
problems or those imposed by the re-
quirements of complex circuitry. The
most obvious problem is that of registra-
tion. Ideally, the three scanning beams
in the camera tubes should scan their in-
dividual scene images exactly, point by
point, throughout the entire raster.
Departures from this exact state show
up first as loss of resolution, and finally
as color fringing or multiple images of
fine detail. In present cameras, registra-
tion is usually sufficiently good so that
color fringing or double images of detail
that are capable of being transmitted in
. the television band are not encountered.
Some resolution in parts of the picture is
lost, however, due to slight misregistra-
tions.

Registration is achieved first by the
use of precision components in the optical
system, the tube deflecting and focusing
assemblies, and the camera tubes them-
selves. The deflecting coils are driven
from a common deflection power supply.
Additional deflection circuitry consists
of skew correction (electrical or me-
chanical) to provide a match between the
two axes of deflection in all three of the
camera tubes. Individual size, linearity,
centering, and skew controls and me-
chanical deflecting-coil rotation provide
additional flexibility of deflection con-
trol to achieve registration. The image
section of the image orthicon provides a
possible source of geometric distortion
that is not present in a tube not having an
image section, such as the vidicon, and
this section must be made as precisely as
possible. The geometry of the optical
system can be made very accurate and
is not subject to change, once properly
set up and adjusted.

A second problem encountered in all
such camera systems is uniformity of
signal output or sensitivity over the
raster. This problem is basic in the sense
that no photosurface is ever perfect. It is
a quality problem in the sense that it is
subject to manufacturing variations.
Extremely close watch is kept on all
photosurface processing and much tighter
specifications are held on the uniformity
of sensitivity of tubes produced for color
cameras. Operation devices or circuits
that can be used to correct for nonuni-
formity of sensitivity are discussed later.

An improved photosurface having
higher response in the blue and red por-
tions of the spectrum would in itself raise
the overall sensitivity of the live cameras
by a factor of at least 2 to 1 because the

green channel is normally padded down
with neutral density filters to match the
sensitivity of the red and blue channels.

Any unwanted signal added to the
video signal can be considered a black-
level error in the sense that it is an
added signal and in the absence of light
shows up as other than a true black signal
and should not occur. The vidicon is ex-
cellent in this respect because in the dark
essentially no current is drawn through
the photosurface and true black-level is
produced. There is some black-level error
in the image orthicon. True black is
representative of full beam return during
the retrace and is reproduced as such.
Errors are introduced by variations of
secondary emission and collection at the
first dynode surface which is partially
scanned by the return beam. These
errors are minor but must be kept to a
minimum by proper manufacturing con-
trol and compensated for as far as pos-
sible by appropriate circuit operation.

Appropriate steps can be taken to
eliminate or minimize these basic diffi-
culties encountered in three-tube camera
systems. Many improvements and modi-
fications can and have been made on the
camera tubes themselves. Improved
geometric uniformity, minimizing of the
amount of magnetic materials, and just
plain careful workmanship have con-
tributed much to minimizing the regis-
tration problem.

There are many operating devices or
circuits that can be used to improve
performance of camera tubes in simul-
taneous color systems. For instance, the
insertion of shading signals mentioned
previously is common practice for the
improvement of black-level performance.
Black-level uniformity cannot be over-
emphasized because small variations in
black-level from channel to channel
cause very pronounced color shifts of
low light portions of a scene. Shading in-
sertion should not be used to produce
high light or sensitivity uniformity over
the raster because such additional signals
will distort the black-level reproduction
of the individual color channels.

A circuit capable of performing the
function of correcting for nonuniform
sensitivity, although complex has been
devised and’ is being used extensively
with the color vidicon cameras. In effect,
it is an amplifier in each color channel
the gain of which is proportional to a
correcting waveform of controllable
shape and amplitude as normally used
for shading insertion. This type of ampli-
fier produces an extremely good match
of tube sensitivities point by point over
the raster counteracting most gradual
uniform variations of sensitivity that
correspond to readily generated wave-
forms.

Another operation that can be used is
cathode modulation shading wherein an
appropriate waveform is applied to the
cathode of the camera tube. In all low-

velocity camera tubes, the scanned sur-
face is driven to the potential of the cath-
ode, and the other element of the storage
capacitor (be it the target mesh in the
image orthicon or the signal electrode
of the vidicon) is maintained at a fixed
potential. Varying the voltage across the
storage element as a function of beam
position by variation of the cathode po-
tential can produce certain effects on
signal output uniformity or sensitivity.
This method works very well on such a
tube as the vidicon because its sensitivity
is a function of the applied signal elec-
trode voltage. The use of this method
with the image orthicon is somewhat
limited because it can correct only for
nonuniform beam landing or target-
mesh spacing; sensitivity is not a func-
tion of the voltage applied across the
storage element in this tube. This method,
however, must be used with caution on
color systems, especially or the vidicon,
because the changing of cathode poten-
tial produces some beam displacement
that impairs registration and also some
slight defocusing by changing the beam
velocity through the tube.

Alternate Systems of Operation
of Camera Tubes for Color Pickup

A highly desirable mode of operation
would be one in which one camera tube
would pick up information and generate
the portion of the color television signal
for the luminance channel. This portion
would be a wide-band signal without
registry problems. The other two camera
tubes would generate narrow-band color
signals. On casual observation, this
solution might seem to be easy and de-
sirable. The luminance or Y channel
would have essentially a human-eye re-
sponse, while the other two channels
would have normal color camera blue
and red channel response. A suitable
matrix unit could subtract appropriate
amounts of red and blue information
from the Y channel and produce a green
signal which, along with the blue and
red signais, could then be used to form
the other components of the color signal
(Fig. 9).

An unfortunate choice (from this
standpoint) is the NTSC specification
for the Y channel.

This is:

Ey = 0.30Ery + 0.59Egy + 0.11Ezy

where 7 is the complementary power law
correction necessary to match the kine-
scope light transfer characteristic. At
present it is not known how any of the
present camera tubes can be operated to
produce a luminance signal Fy or a sig-
nal capable of being transformed to meet
these specifications without matrixing
with the other color signals and introduc-
ing registry problems as a result of signal
addition.

Whether a linear camera tube or non-

Neuhauser: Camera Tubes for Color TV Broadcast Service : 641

‘

MATRIX

RBY CAMERA

Fig. 9. Block diagram

and channel response of

color television system
AND GAMMA utilizing one channel for
wer luminance (Y) portion

of the color signal and
the other two channels for
signa, blue and red portions.

406) 5000 6000 7000 4000
WAVELENGTH —ANGSTROMS

COLOR CHANNEL RESPONSE

5000 7000
WAVELENGTH—ANGSTROMS
RESPONSE AFTER MATRIX

4

OPERATION

linear tube is used, the form of the pro-
duced signal will be as follows:

For a linear device such as image
orthicon::

Ey = KiEr + +

K,, Kz and K; being constants determined
by the optical filters.

Gamma correction of this signal would
produce a signal of the form:

Eyy = (KiEr + + KiEs)y
which is not equal to the required form:
Eyy = K,Ery K:Eg@y +

A nonlinear device such as vidicon
would produce a signal of the following
form:

Ey8 = (KiEr + KrEg + KiF

where 8 is the “gamma” of the pickup
tube.

This form too is not adequate and
would produce errors in color repro-
duction. There is no presently known
way of operating on this signal to form
the Y or Y7 signal as specified in the
NTSC color standards.

Single-Tube Camera System

The desirability of a single tube cap-
able of generating all of the necessary
color video information is fairly obvious
in that the relatively complex optical
equipment, deflection circuits, and reg-
istry controls would be unnecessary.
Secondly, nonuniformity of photosensi-
tivity, etc., would not produce color
shading or color shift in the reproduced
picture.

At present the only approach that
seems at all practical to the problem of
producing the necessary signals to form
a color picture from one tube is that de-
scribed by P. K. Weimer, et al.,) at
1955 IRE Convention.

This tube, as described, is a photo-
conductive tube employing vertical color
filter strips registered with appropriate
signal output strips that are tied to the
proper bus connections. It produces
three simultaneous signals at three out-
puts. This approach uses a single scan-
ning beam requiring no convergence
or nonperpendicular beam landing in-
cidence. Secondly, no accurate timing is
required to detect color information.
Accurate timing would be necessary if
the tube were an image-orthicon type
in which the signal information is con-
tained in a single return beam.

The technology of making this type
of tube with the precision required is ex-
tremely complex and difficult. The prin-
ciples of operation and signal generation
are sound and it has been demonstrated

_to perform the functions required satis-

factorily. However, more sensitive photo-
conductors are required for satisfactory
operation in live pickup than are avail-
able at the present time.

Acknowledgments

The success of color television camera
tube performance is due in a large part
to the work of R. B. Janes, B. H. Vine,
F. S. Veith, F. D. Marschka, and A. A.
Rotow of the RCA Lancaster Engineer-
ing Section, in developing and adapting
these tubes for color camera operation.

Perhaps an even greater credit should
be given the camera tube factory engi-
neering personnel for their constant im-
provement of the camera tube uniform-
ity, quality and performance. Many en-
gineers under the direction of J. K.
Johnson and H. M. Hambleton have
contributed much over the years to make
the manufacture and use of these com-
plex tubes for color possible.

Bibliography

1. P. K. Weimer, S. Gray, H. Borgan, S. A.
Ochs and H. C. Thompson, “The tricolor
vidicon — an experimental camera tube for
color television,” Abstract in Proc. IRE, 43:
370, Mar. 1955.

. R. G. Neuhauser, “‘Vidicon for film pick-
up,” Jour. SMPTE, 64: 142-152. Feb. 1954.

. R. G. Neuhauser, F. S. Veith and A. A.
Rotow, “Image orthicon for color cameras,”
Proc. IRE, Jan. 1951.

. A. A. Rotow, “Reduction of spurious signals
in image orthicon cameras,” Broadcast News,
Feb. 1955.

. R. B. Jones and A. A. Rotow, “Light trans-
fer characteristics of image orthicons,””
RCA Review, Sept. 1950.

. B. H. Vine, F. S. Veith and R. B. Janes,
“Performance of the vidicon, a small de-
velopmental television camera tube,”’ RCA
Review, Mar. 1952.

. J. D. Spradlin, “The RCA color television
camera chain,” RCA Review, Mar. 1952.

. F. W. Millspaugh, “RCA Color Camera,
TK40A,” Broadcast News, Jan.—Feb. 1954.

. Sachtleben, Parker, Allee and Kornstein,
“Image orthicon color television camera
optical system,” RCA Review, Mar. 1952.

. H. N. Kozanowski, ‘‘3-Vidicon color film
camera,” Broadcast News, May-June 1954.

Discussion

E. F. Pedersen (RKO Teleradio, Burbank, Calif.) :
You mentioned that by adjusting the signal
electrode voltage you can adjust the sensitivity
within limits. Could you specify these limits
and also the effect this has on signal-to-noise
ratio?

Mr. Neuhauser: On the vidicon tube we would
like to suggest that for film operation the high-
lights of the image on the tube have at least 100
to 200 ft-c. You can adjust the setup so that
you have less light and higher voltages applied
to the signal electrode and still come out with
the same signal output. This would mean that
the signal-to-noise ratio is maintained the sanie.
What you would lose would be speed of response
of the camera-tube photosurface. However, if
you merely increased the signal-electrode voltage
and decreased the light level too drastically,
necessitating gain control to bring up the signal
output, you would degrade the signal-to-noise
ratio of the video signal. Basically you would
trade sensitivity for lag.

Mr. Pedersen: In other words, if you traded
signal-electrode voltage for light, as you lower
light and up signal-electrode voltage the principal
effect would be one of lag?

Mr. Neuhauser: That’s correct. You would
eventually get to the point where you would also
have poor black-level; that is, where your
dark currents would become so high that you
would have a poor or uneven black-level.

December 1956 Journal ofthe SMPTE Volume 65

E
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642

Switching and Controls for Color
and Monochrome TV Studios

The approach to the problem of lighting control equipment design resolves itself
into two basic areas, that of switching and that of dimming. Switching involves the

ability to connect any lighting loads in the studio to any dimmer.

Dimming in-

volves the ability to modify the intensity of any of the lights in a convenient

manner.
this is accomplished.

most common type of interplug-
ging device is the retractable cord and
plug type of jack panel (Fig. 1). Each
lighting load terminates in a male plug.
The various stage dim and non-dim con-
trol circuits terminate in female jacks
(Fig. 2). It is possible to connect any
light to any dimmer by inserting its plug
into a jack. Since each dimmer is repre-
sented by more than one jack, it is pos-
sible to connect several lights to the
same dimmer. This type of interplug
panel is usually the most economical to
build.

For systems of 300 loads or less it is
usually possible to make panels with
100% flexibility, that is, it is possible to
connect any load to any dimmer. As the
number of loads in the studio increases,
the size of the panel becomes larger and
somewhat unwieldy, and in many cases
some of the load plugs will not reach
some of the jacks. It is easy for the opera-
tor to determine which dimmers are in
use, and it is relatively simple to deter-
mine the loading on each dimmer.

However, the general appearance of a
fully plugged panel is unsightly, and it is
not easy to determine where a specific
load plug is connected, as it is necessary
to trace the wiring from the plug back to
the identifying tag on the panel, or to
search for the identifying tag on the plug

vention at New York by James W. Thompson,
Century Lighting, Inc., 521 W. 43 St., New York
36.

(This paper was received on November 12, 1956.)

FROM

DIMMERS

Loaos
N N

Fig. 2. Retractable cord interplug.

This paper describes some of the equipment and methods by which

handle itself in the midst of a jumble of
plugs.
Cold Patching

Since the plug and the jack are sub-
ject to arcing when a plug is inserted or
removed under load, various modifica-
tions have been developed to minimize

By JAMES W. THOMPSON

or limit the effect of this arcing. One
solution has been the use of a heavy-
duty plug and jack which will withstand
this abuse for a long period of time with
only negligible deterioration.

Another approach had been to add a
device to the plug and jack which will
automatically open the circuit as the plug
is being inserted or withdrawn. A circuit
breaker may be mounted next to the
jack. A skirt om the base of the plug auto-
matically trips the breaker as the plug is
withdrawn. After the plug has been re-
inserted, it is necessary to reset the
breaker by hand.

In another system a microswitch is
mounted on the jack, with an actuating
cam built into the plug. This device

eae

—

Fig. 1. Console type autotransformer dimmer board with dimmers on left and retract-

able cord type interplug section on right.

FEMALE
JACKS ROTARY

SWwiTcH

\

*~,-°

COUNTERBALANCE

FROM
DIMMERS

Load
BREAKER

N

Fig. 3. Rotary switch interplug.

December 1956 Journal of the SMPTE Volume 65

LOAD
BREAKER
MALE
PLUGS
N
643

Fig. 4. Electronic dimmer rack with 30 5-kw dimmers.

?

opens the control circuits of an electronic
dimmer causing the dimmer to black out,
rendering the circuit open. This is usable
only with electronic dimmers, and it is
the only known device which eliminates
the arcing.

Rotary Switches

In an effort to improve the interplug
panels, several types of switching de-
vices which do not use retractable load
cords have been made. These use rotary
switches with multiple positions (Fig. 3).
One switch is required for each lighting
load. As many positions are provided on
each switch as there are dimmers in the
system. The mechanics of switch design
usually require a maximum of 24 posi-
tions for such heavy-duty switches. This
limits flexibility because a light may be
connected to only one of 24 control cir-
cuits. To overcome this problem in
larger systems, the louwds are usually
grouped into multiples of 24; therefore,
the first group connects to the first 24
dimmers, the next group to the next 24
dimmers, and so forth.

Rotary switches are also made with
the cold patching device, so the circuit is
automatically opened as the switch is
rotated. One such switch mounts a cir-
cuit breaker next to the switch handle
which automatically trips as the handle
is pulled to rotate. Another design offers
a mercury switch with an interlocking
dog which engages the rotary handle, so

that it is not possible to rotate the switch
handle until the mercury switch has been
open. These panels look neater and more
organized than the plug-and-jack type.

Another interplugging means has bor-
rowed the principle of the cross metering
system. This uses a series of vertically
mounted bus bars, one bus for each light-
ing load. Behind these are horizontally
mounted bus bars, one for each dimmer.
By inserting a jumper pin, or plug, be-
tween one of the horizontal and one of
the vertical bars it is possible to connect a
stage lighting load to a particular dim-
mer. The problems of interlocking this
device to make it safe, and interlocking so
that the same lighting load cannot be
connected to two dimmers simultane-
ously are difficult to overcome; therefore,
this type of device has not yet become
popular in television work.

Dimming

The dimming equipment as originally
supplied for television studios was very
similar to that used in the legitimate
theater. It was not until these systems had
been in use for several years that the
differences between the lighting control
problem in the television studio and the
theatrical stage were generally under-
stood.

On a theater stage, the sets are located
in the same general area at all times. The
scenery may be changed between acts,
but the same lights are focused on the

same areas. In television work, several
sets are usually in place at one time, and
different groups of lights are used to
eliminate each one. Therefore, the con-
trol function consists of sequential con-
trol of the same lights in the theater, but
simultaneous control of different groups
of lights in the studio.

Auto Transformers

The most common type of dimmers
used in television are autotransformers
(Fig. 1). These are made in 2500-w or
6000-w capacities. The dimmers are
supplied with mechanical interlocking
handles which make it possible to con-
nect several dimmers simultaneously to a
master handle. It is possible to dim
several groups of lights simultaneously
with one handle, but all dimmers so
interlocked must be at the same inten-
sity, and must all respond simultaneously
and to the same degree. The lighting
cues must therefore be simple in effect.
Autotransformer dimmers are the most
economical! to build, install and main-
tain. They operate quietly and produce
very little heat; however, their size,
weight and inertia limit their usefulness
in a large studio.

Motor-Driven Dimmers

In order to reduce the size of the con-
trol panel, motor-driven auto trans-
former dimmers are available. The dim-
mers are located remotely, and a small
control panel is used to energize the dim-
mer motors. These controls consist of
simple “‘start-stop” switches, or of more
elaborate positioning controllers con-
sisting of a potentiometer similar in
appearance to a miniature dimmer
handle. The potentiometer is moved to
the desired intensity setting, causing a
relay bridge network to energize the
motor automatically until the dimmer
reaches the predetermined position.
There is a response time-lag from the
setting of the potentiometer until the
motor has driven the dimmer to the new
intensity. This lag is about 6 sec from
full bright to full blackout.

Electronic Dimmers

An electronic lighting-control system
using thyraton tubes as dimmers is
widely used in television (Fig. 4). These
dimmers incorporate the advantages of a
preset system whereby the intensity of all
of the lights can be preset for several
cues in advance. By manipulation of the
master controls any of these preset light-
ing scenes may be energized in any
sequence. Proportional mastering and
fading are possible. The dimmers them-
selves feature infinite loading ratio and
instantaneous response, and are avail-
able in capacities to 8-kw. The dimmers
themselves are about the same size as a
comparable auto transformer, but be-
cause they produce noise and heat, they
are usually remotely located. Filters are

644 December 1956 Journal of the SMPTE Volume 65

at.
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a
T
a
q
J

incorporated into the thyraton circuit-to
increase stability and to suppress har-
monics which would otherwise affect the
audio and video circuits.
Magnetic Amplifiers

The latest addition to the field of
theatrical dimmers is the magnetic
amplifier. This is an outgrowth of the
saturable core reactor dimmer, but with
improved response and increased gain.
Magnetic-amplifier dimmers lend them-
selves to the same type of control as elec-
tronic dimmers. The dimmers are larger,
heavier, and more costly than comparable
thyratron types. Their speed of response
is about 4 sec, and their load ratio is
about 30:1. Their inherently long life

and relatively heat-free operating charac-
teristics make them compare favorably
with thyratrons. New core materials and
winding methods may reduce the weigist
and increase the response speed.

One manufacturer has annousiced a
package unit which features a magnetiz-
amplifier input stage driving a satrable-
core reactor stage which includes its own
booster transformer. Although slightly
slower in response, this combination unit
combines most of the desirable features of
magnetic amplifiers and thyratrons.

The Future

As television lighting systems become
larger and more complex, remote control
systems now in use are rapidly becoming

Calculation of Candlepower

and Color Temperature

of Tungsten Lamps

Over the range of greatest interest in photography, the candlepower and color
temperature of tungsten lamps may be calculated with satisfactory precision by
the use of simple exponential equations. Detailed examples are given which
illustrate the application of these equations. The constants and exponents in
these equations have been determined for several commonly used lamps. These
have been arranged in a set of tables designed for convenient reference.

tungsten lamps are widely
used as light sources in the sensitometry,
printing, projection and viewing of
photographic films. In these applications
two properties are of primary interest:
(1) the luminance of the lamp, expressed
in terms of “candlepower” and (2) the
relative spectral energy of the radiation,
specified with sufficient accuracy by
stating the “color temperature” of the
lamp filament.

For tungsten lamps, the use of these
visual properties to characterize the
radiation is thoroughly justified. An
incandescent tungsten lamp filament
operated at a given color temperature
produces the same spectral energy, to a
high degree of approximation, as a
blackbody radiator at the corresponding
temperature in degrees Kelvin. Thus,
determination of the color temperature
of a lamp provides the essential knowl-
edge of the relative spectral energy that
is produced by the lamp. Once the rela-

A contribution submitted November 14, 1956,
by A. J. Sant and A. J. Leta, Color Technology
Div., Eastman Kodak Co., Kodak Park Works,
Rochester 4, N.Y.

tive spectral energy is known, specifica-
tion of the candlepower of the lamp
uniquely determines the intensity of the
radiation at every wavelength. The
practice of specifying the physical proper-
ties of the radiation by means of its
visual properties has the further ad-
vantage that relatively limited equip-
ment is required to measure the neces-
sary quantities. These considerations
have led to fairly widespread adopticn of
lamp calibration methods based upon
visual properties.

Considerable work has been done
empirically relating the luminous output
and color temperature of tungsten lamps
to the input power cr to voltage and
current separately.

Weaver and Hussong have reviewed
the empirical relationships that have
been used and offer an excellent discus-
sion and evaluation of them in “A Note
on Tungsten Lamps.”*

In most photographic work, lamps are

* K. S. Weaver and H. E. Hussong, “A note on
the color temperature-candlepower character-
istic of tungsten lamps,” J. Opt. Soc. Am., 29:
16-19, Jan. 1939.

obsolete. Reliability and flexibility are
important, but it is more important to
reduce the quantity and complexity of
the controls. Further reduction of the
individual control size is not the answer.

One approach seems to be to do some
or all of the interphugging at the control
end ef the circuit. Thus one control
would operate several dimmers. For this
to be practical it is necessary to accept
certain limitations of dimmer response
and loading characteristics and still stay
within cost limitations. The use of mag-
netic memory banks to take the place of
the preset panel is theoretically possible,
but at present, the cost of the ‘“‘read-out”
stage is prohibitive but it still remains a

possibility.

By A. J. SANT
and A. J. LETA

seldom operated far below 2650 K be-
cause of the low luminous output that is
obtained. Considerations of useful life
prohibit the operation of calibrated tung-
sten lamps at temperatures much in
excess of 3250 K. lt was felt that
empirical relationships that would ade-
quately describe lamp behavior over
this limited range would therefore be of
practical interest.

Our experience has shown that the
behavior of lamps over the range in
color temperature from 2650 to 3300 K
might be adequately described by rela-
tionships of the form

T2 (CP); _
log 7; = els (CP)2

b log = ¢

where T = color temperature in degrees K
CP = candlepower
V = lamp voltage
7 = lamp current.

Relationships of this form relating
candlepower, voltage and current have
been in common use by lamp manufac-
turers and other workers for many years.
This type of relationship has been far
less widely used for color temperature.
The purpose of the present study was
to examine the “fit” that is obtained
when the logarithms of the candlepower,
voltage, current and color temperature
are related in the manner described
above over the range 2650-3300 K.
The study included a number of lamps

December 1956 Journal of the SMPTE Volume 65

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Table 1. Current as Dependent Variable.

Color Temperature
500-w, 110-v #5
500-w, 110-v #7
500-w, 110-v #8
Av. 500-w, 110-v
1000-w, 120-v
100-w, 20-v
Average

Vol: tage

500-w, 110-v 45
500-w, 110-v 47
500-w, 110-v #8
Av. 500-w, 110-v
1000-w, 120-v
100-w, 20-v
Average

Candlepower

500-w, 110-v 45
500-w, 110-v #7
500-w, 110-v 48.
Av. 500-w, 110-v
1000-w, 120-v
100-w, 20-v
Average

commonly used in the sensitometry and
projection of photographic films within
the Color Technology Div. of the East-
man Kodak Co. The equations derived
are intended to be used with limited
calibration data to provide the engineer
with a useful set of equations by means
of which he may anticipate the behavior
of a lamp over the normal range of use.

Procedure

Lamps Studied: The sample of lamps
studied consisted of three 500-w, 110-v
projection lamps having T-20 clear bulb
and a C13 filament; one 100-w, 20-v
lamp having a spherical, T-8, clear bulb
and a CC2V filament; and one 1000-w,
120-v projection lamp having a T-12,
clear bulb and a C13D filament.

Three of the 500-w projection lamps
were studied because that type of lamp
is most commonly used in the Eastman
Kodak Co. in sensitometers. The 100-w
lamp is less commonly used and was

Table III. Color Temperature as De-
pendent Variable.

2¢
Voltage
500-w, 110-v #5
500-w, 110-v #7
500-w, 110-v #8
Av. 500-w, 110-v
1000-w, 120-v .
100-w, 20-v
Average
Candlepower
500-w, 110-v #5
500-w, 110-v #7
500-w, 110-v 48
Av. 500-w, 110-v
1000-w, 120-v
100-w, 20-v
Average

Current

500-w, 110-v #5 .
500-w, 110-v 47
500-w, 110-v 48 .
Av. 500-w, 110-v
1000-w, 120-v
100-w, 20-v .
Average

December 1956 Journal of the SMPTE

selected because the unusual filament
design (helically coiled coil) would pro-
vide interesting data on the effects of
filament design upon the results ob-
tained. The 1000-w. lamp is commonly
used both in projectors and in certain
types of high-intensity sensitometers.
The bulb design for this lamp is radically
different from that of the other types
studied.

In calibrating a lamp for color tem-
perature, the current through the lamp
was adjusted until the light produced was
identical in color to that produced by a
standard lamp operated at the desired
color temperature. The device used for
matching was a Lummer-Brodhun pho-
tometer. The usual precautions were
taken to eliminate the effects of differ-
ences in color due to differences in the
two sides of che photometer head,
geometry, etc. The accuracy of the
specification of color temperature is
estimated at +0.5%. The precision of
the measurements is estimated at
+0.25%.

For the determination of candlepower,
the distance was found at which the
lamp produced a response on a precision
photoelectric foot-candle meter (of the
barrier-cell type) equal to that produced
by a standard lamp at a given distance.
The candlepower of the lamp was then
calculated from the known illumination
produced by the standard lamp at the
foot-candle meter and the distance from
the foot-candle meter to the lamp being
calibrated. The effects of drift and
fatigue in the barrier cell of the foot-
candle meter were carefully minimized.
The estimated accuracy of the specifica-
tion of candlepower is +2%. The pre-
cision of the measurements is estimated
at +1%.

Calculations and Results

Linear relationships were derived by
the method of least squares relating the
logarithms of lamp candlepower, voltage
and color temperature to the logarithm
of lamp current.

From these basic relationships, linear
equations were derived in which the
logarithm of each parameter taken as
dependent variable is expressed as a linear
function of the logarithm of each of the
remaining three parameters. Thus for
each lamp 12 equations were obtained
of the form y = mx + 6. The coeffi-
cients, m and 6, which apply to each
relationship for each lamp in the sample
are compiled in Tables I through IV.

Since three 500-w lamps were studied,
there are three entries in the tables for
500-w lamps and a fourth entry which
gives the average of the results for
the three lamps. Also included in the
tables, where current appears as de-
pendent or independent variable, are
columns denoted 2¢. These express the
probable range of the deviations from
the straight-line relationships owing

Table II. Voltage as Dependent Variable.

Color Temperature

500-w, 110-v #5 . .
500-w, 110-v #7 .
500-w, 110-v #8 .
Av. 500-w, 110-v.
1000-w, 120-v .
100-w, 20-v .
Average

Candlepower
500-w, 110-v 45 .
500-w, 110-v 47 .
500-w, 110-v #8 .
Av. 500-w, 110-v.
1000-w, 120-v .
100-w, 20-v .
Average

Current

500-w, 110-v #5 .
500-w, 110-v 47 .
500-w, 110-v #8 .
Av. 500-w, 110-v
1000-w, 120-v .
100-w, 20-v .
Average

either to systematic nonlinearity in the
basic relationshjps or to experimental
error.

Application of the Tables

The values of m and 6 given in the
tables apply to linear equations relating
the logarithms of the lamp parameters.
These have the form

log y = mlog x + 6 (1)

where y is the parameter taken as dependent
variable and x is the parameter taken as
independent variable.

From these equations, exponential
relationships can be derived. These take
the form

y = b’x™ (2)
where is the antilog of 5.

To find the change in a given param-
eter that results when another param-
eter is changed slightly, differential
relationships may be used. These are

Table IV. Candlepower as
Variable.

Voltage

500-w, 110-v #5
500-w, 110-v #7.
500-w, 110-v #8. .
Av. 500-w, 110-v
1000-w, 120-v_.
100-w, 20-v
Average .

Color Temperature
500-w, 110-v #5.
500-w, 110-v #7.
500-w, 110-v #8. .
Av. 500-w, 110-v .
1000-w, 120-v
100-w, 20-v_.
Average .

Current

500-w, 110-v #5.
500-w, 110-v #7.
500-w, 110-v #8. .
Av. 500-w, 110-v_ .
1000-w, 120-v
100-w, 20-v
Average .

era.

Volume 65

m 2¢ m 5 2e
1.460 —4.451 .003 . 2.615 —7.134 =
1.444 —4.396 .0004 . 2.586 —7.030
1.442 —4.387 0006 . 2.589 —7.048 —-
1.449 —4.411 .001 . 2.596 —7.070
1.454 -4.710 .002 . 2.605 —7.133
1.447 —4.386 .003 . 2.590 —7.807
i 558 469 .002 306 —
558 470 .305 1.064
557 - .002 . 306 1.055 —
558 - .466 .002 .306 1.058
558 229 002 .301 .969
: 559 024 002 my .299 .583 —
171 121 004 =.004
.170 124 004 Ore .842 .003
170 126 004 .828 .003
.170 124 004 1.792 .836 .003
168 311 .003 411 .005
.167 302 .003 .043 .004
|
3.263 — 3.444 —
. 3.279 — 3.488
3.267 — 3.446 .
3.270 — 3.459
. 3.327 — 3.224 -
. 3.342 — 1.949
. 3.296 —
. 8.531 —26.721
8.479 —26.540 —
8.459 —26.470 -
8.490 —26.577 -
. 8.668 —26.959 —
. 8.654 —28.037 —
. 8.558 —
685 3.049 .002 844 .025
693 3.042 .0004 .866 ;
.690 3.045 .001 861 .725 .025
688 2.896 .001 .964 1.857 .020
.691 3.031 .002 1.805 .020
646

immediately derived from Eqs. (1) and
(2) respectively, as

d (log y) = md (log x) (3)
dy = mb'x™—'dx, (4)

Using Eq. (4), the per cent change in y
corresponding to a per cent change in xis
mb'x™"\dx _

b'x™

100 m = m 100% (5)
x x

100% = 100

or the per cent change in y equals m times
the per cent change in x.

While Eq. (5) is very satisfactory for
small changes, it should not be used
where large changes in the lamp param-
eters are involved. For large ranges
of the variables, Eq. (1) or (2) should be
used.

As indicated in the illustrative exam-
ples below, the values of 6 are a property
of each individual lamp and vary
markedly even among lamps of the same
type. Hence the tabulated values of 6 are
not to be used in calculations involving
lamps other than the ones for which they
were obtained.

The range of application of the tables
is defined by the limits 2650 K and 3300
K. Use of the tables beyond these limits
will involve a loss in accuracy.

Hlustrative Examples

Three examples are given below of
typical practical problems in which the
results of the present study may be used
to provide the solution. The examples
cited are solved in detail to show ex-
plicitly the formal mathematical pro-
cedure that is involved and to point out
the physical considerations that must be
taken into account.

Example 1

A printer is being designed. An
ammeter will be used to control lamp
current. The lamp current must be con-
trolled sufficiently well that a precision
of +0.005 log E is realized at the expo-
sure plane. What must the precision of
the ammeter be to realize this precision
in log E?

Solution: Take candlepover (CP) as the
dependent variable and current (J) as
the independent variable and make use
of Eq. (3) in the text. The average value
of m over the entire sample is used. For
this example Table IV gives the value
5.906. Equation (3) states that

d (log CP) = md (log /).

Using the value 5.906 for m and 0.005
as the allowable increment in log candle-

power:
Sant and Leta:

0.005 = 5.906 d (log /)
0.00085 = d (log J).

Thus a change of 0.00085 in log cur-
rent produces a change of 0.005 in log
E. A change of 0.00085 in log units cor-
responds to 0.2%. The ammeter must
provide a precision of 0.2% of the scale
reading.

Example 2

A 500-w, 120-v lamp is to be used in a
printer and operated at 2850 K and 3000
K. An estimate of the current (J), voltage
(V), and candlepower (CP) at each of
these settings is required. According to
the manufacturer’s specifications, the
lamp burns at 3200 K when operated at
its rated voltage and is rated at 1200 cp.

Solution: The average values of m taken
over the entire sample may again be used.
The values of 6 that will apply on the
average for this lamp type can be ob-
tained by using the manufacturer’s
specifications. According to these specifi-
cations, at 3200 K the voltage is 120, and
the wattage is 500. Solving for current:

500
120 = 4.17 amp.

Thus at 3200 K, V = 120, 7 = 4.17,
CP = 1200.

We now take current, voltage and
candlepower in turn as dependent vari-
ables and use the average values of m
given in the tables under Color Tempera-
ture (CT). Insert these values of m into
the equations of the form:

that apply
in each case. (1)

log y = mlog x + 6

The result is:

log = 1.449 log CT + (1a)
log = 2.598 log CT + be (1b)
log CP = 8.558 log CT + 43. (1c)

Substituting in these equations the
values of V, J and CP that apply at 3200
K, and solving for 5, 62, and 43, we find:

b, = — 4.459
bz = — 7.027
bs = —26.918.

Thus, the final relationships are:

log = 1.499 log CT — 4.459
log V_ = 2.598 log CT — 7.027
log CP = 8.558 log CT —26.918.

When values of 2850 and 3000 are
substituted in these equations, we find:

At 2850 K V = 88.9
I= 3.52
CP = 445
at 3000 K V = 102
= 3.80
CP = 691.

Example 3

A 500-w lamp is to be used in a
sensitometer. Calibration of the lamp
shows that the lamp draws a current of
4.0 amp and has a candlepower of 900
when operated at 3000 K. What will the
current and candlepower be at 2850 K?

Solution: The procedure is analogous
to that used in the previous example.
The average values of m taken over the
entire sample, and the basic relationship
(1) are used. The values of 6 are found
by substitution in the relationships (1)
of the values provided by the lamp cali-
bration at 3000 K. When values of 6
thus obtained are substituted in the rela-
tionships, we find:

log I = 1.449 log CT + (—4.436)
log CP = 8.558 log CT + (—26.803).

When 2850 is substituted for C7 we
find that at 2850 K:

Conclusion

The results of the study indicate that
the value of 6 depends upon lamp watt-
age and rated voltage, as one would ex-
pect. The values of m however show very
little variation among the types studied.
In fact the magnitude of the variation in
m among lamp types is the same as that
among lamps of the same type. Thus, one
may conclude that the value of m is rela-
tively constant for a variety of filament
and bulb designs. It should be noted that
in the solution of the problems given as
examples the average value of m over the
entire sample (given at the foot of each
set of tables) was invariably used.

This procedure was not employed in
determining the value of 6 in any of the
examples for reasons that are obvious
from a study of the tables (see especially
Table IV). When a _ representative
value of 6 for a given lamp type is re-
quired, the value of #4 is estimated using
the manufacturer’s specifications for that
type of lamp, as we have illustrated in
Example 2 above. When the value of 6
for a particular lamp is required, the
lamp must be calibrated for voltage,
candlepower, and current at a single
color temperature and the value of 6
calculated as shown in Example 3.

The overall agreement between the
values of m obtained in this study and
those given for gas-filled lamps in General
Electric Lamp Bulletin LD-1 is good.
There is enough difference however to
warrant the use of the values given here
for lamps of the types studied.

The method is recommended for all
work except that of the highest precision.
For work requiring the highest precision,
it is recommended that the lamp be inde-
pendently calibrated at each color tem-
perature.

Candlepower and Color Temperature of Tungsten Lamps 647

2
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i

Densitometry of an Embossed

Kinescope Recording Film

The requirements for image analysis of Eastman Embossed Kinescope Recording
Film, Type 5209, are discussed. The actual distribution of density of the embossed
film image is shown. The optical requirements necessary to analyze these images are
similar to those used in projection. It is further shown that these requirements can
. be made by a comparatively simple modification of a Westrex Densitometer. The
results of sensitometric evaluation of satisfactory color images measured on this

modified instrument are shown.

, use of an embossed, blue-sensi-
tive black-and-white film for the record-
ing of color television signals was de-
scribed in an earlier paper.' That dis-
cussion generally concerned an_ ideal
film and optical system. In practice,
there are many optical and photographic
variables which tend to compromise this
ideal. For the system to be successful,
these variables must be kept under con-
trol. It is the purpose of this paper to de-
scribe an instrument which will satisfac-
torily measure the photographic char-
acteristics of the image. Measurements
of this image can then be used to evaluate
the quality of the optical components
used in its recording and reproduction.

In an ideal system, the image of the
red filter band or corresponding aper-
ture, for example, would fall entirely
within the area allotted to it behind each
lenticule. Each image would be in the
same position relative to the optical axis
of its lenticule. Usually these conditions
cannot be exactly met. Neither the
camera objective lens nor the lenticule
is perfect, and, since both are of high
aperture (f/2.3), aberrations are present
in the image. Diffusion of light between
the film and the aperture also degrades
the image.

After this imperfect image of the aper-
ture enters the emulsion, light scatter
within the emulsion layer tends to diffuse
it somewhat farther. When this exposed
image is processed, factors which would
cause a spreading of the image in the
processing stage may also degrade the
quality of the color separation. It be-
comes fairly obvious that some control
over the distribution of density in the
color image must be maintained if the
system is to operate satisfactorily.

Distribution of Density

The two photomicrographs shown in
Fig. 1 illustrate the nature of the film

Communication No. 1856 from the Kodak
Research Laboratories, presented on Octobe
11, 1956, at the Society’s Convention at Los
Angeles by T. G. Veal for the authors, W. R. J.
Brown (now at Boston University), C. S. Combs
and R. B. Smith, Research Laboratories, East-
man Kodak Co., Rochester 4, N. Y.

(This paper was received on October 15, 1956.)

image formec| in a well-controlled optical
system, wher exposure is given through
the red-separation aperture only or
through the blue-separation aperture
only. The clumps of grains are quite
well confined to the proper geometric
location but there are a few density-pro-
ducing grains between these areas.
Since exposure conditions were intended
to produce density only in areas corre-
sponding to the one aperture position
indicated, density in the other areas of
the emulsion was produced by the factors
discussed previously.

The actual distribution of density
across the film can perhaps be evaluated

Embossing

Base

Emulsion”

|

U

By W. R. J. BROWN,
C. S. COMBS and R. B. SMITH

somewhat better by the microdensitome-
ter traces shown below the photomic-o-
graphs in Fig. 1. The microdensitometer
traces were obtained by moving the
film image past a long narrow slit before
making the measurements. The em-
bossed surface of the film base was
covered by a liquid of the same index of
refraction as the film base. This ren-
dered the base surface effectively flat as
far as the light beam was concerned.
Thus the microdensitometer optics re-
corded only variations in density of the
silver image.

Although the desired density differ-
ence in the film, between the exposed
and the unexposed areas, was meant to
be as great as possible, these microden-
sitometer traces indicate that, in actual
practice, it was restricted by the many
factors which contributed to its forma-
tion. The microdensitometer trace pro-
vides a unique description of the dis-
tribution of image behind the emboss-
ings, by measuring the density differ-

4

Red exposure

Blue exposure

Fig. 1. Photomicrographs and microdensitometer traces of embossed film images.

648 December 1956 Journal ofthe SMPTE Volume 65

| | |
}
i
>
=
: 77)
|
=

Fig. 2. Schematic diagram of an illumina-
tion system for embossed film densitom-

etry.

ence between the image itself and the
adjacent image areas which have re-
ceived no exposure. This is a measure of
the color separation in the process. The
greater the density difference between
the image and the adjacent areas the
greater will be the color separation
within the recorded image.

Microdensitometry of the color-sepa-
ration images is undoubtedly the most
analytical measurement which can be
made of the nature of the image. The
actual density distribution behind each
embossed lens may be compared to the
ideal image distribution. To the extent
that there is density in areas which re-
ceived no exposure, the image is imper-
fect. This unwanted density is produced
by poor imaging in the optical system
or by light scattered in the emulsion or
at the embossed surface. The maximum
color saturation possible with the film
is the colorimetric mixture of the system
primaries controlled by the actual den-
sity distribution in the emulsion. If the
density in the red area, for example,
averages 1.3 more than the density in the
adjacent area, the resulting color upon
projection will have twenty times as
much green and blue primary present as
red primary. The greater this density
difference, the more saturated will be
the resulting color.

Modified Densitometer

The advantages of microdensitometry
are by no means slight. Most microden-
sitometers, however, are quite compli-
cated and provide problems in instru-
ment technique not normally found in
the laboratory.” Essentiaily, it is the den-
sity of the image area which is required.
This suggests that a properly modified
densitometer could provide the required
measurements. Such a measuring instru-
ment should be no more complicated to
operate than a standard densitometer.
It should simulate the optical system in
which the film is to be used, and it should
give reproducible results.

Perhaps the simplest way to simulate
the optical system with which the film is
to be used is to arrange the illumination
in the densitometer so that all of the light
falling upon the film will be focused by
the lenticules so as to pass through one
of the image separation areas of the

film. If the detector in the densitometer
then collects all the light passing through
the film, the density in the image sepa-

: ration area in question will be measured.
“Similarly, the other image areas can be

read by changing the direction of the
light incident upon the film.

A simple but adequate system is
shown in Fig. 2. In this case, light is
allowed to pass through an aperture
placed at the focal point of the lens.
The aperture is oriented relative to the
optic axis of this lens so that light emerg-
ing from the aperture will be collimated
by the lens and will strike the film at a
fixed angle relative to the optic axis of
the system. This parallel light is then
focused by the lenticules on the film base
to form an image of the rectangular
aperture in the emulsion area. This is
shown in the enlargement of the cross
section of the film base in Fig. 2b.

In order to have the light pass through
the proper image area, the angular size
of the aperture measured from the prin-
cipal point of the objective lens must be
identical with the angular size of the
image measured from the embossed film
surface. When this condition is met, the
other image areas will not be illumi-
nated. Light will pass only through the
desired image area, and the densitometer
will indicate the correct density.

Fortunately, some densitometers are
designed in such a way that an optical
system similar to that shown in Fig. 2 is
already a part of the design of the instru-
ment. In this case, only slight modifica-
tions need be made to meet these optical
requirements. A popular densitometer
which can easily be modified is the West-
ern Electric Densitometer, Type RA-
1100B, commonly known as the Westrex
Densitometer.*

In this densitometer, an objective lens
forms an image of the light source upon
the film surface placed upon an aperture.
It is possible to place an aperture at the
front focal plane of this objective lens so
that the lens acts effectively in the same
way as the lens in Fig. 2. Light from any
point on the front focal plane of the lens
leaves the rear of the lens as parallel
light, as shown in a sketch of part of the
optical system in Fig. 3. This parallel
beam is then focused by the lenticules
on the base of the film and is directed
through the appropriate image area.

The shape of the aperture placed at
the front focal plane of the objective lens
need only be made to subtend the same
angle relative to the principal points of
the lens as does the aperture in the pro-
jection system used for the film. In this
way, exactly conjugate results can be
obtained from the densitometer to those
obtained in the projection system.

In normal color kinescope recording,
the angular size of the aperture is such
that the red and the green images are
exposed by an aperture subtending ap-
proximately f/10 at the fiim surface.

Red and green apertures are located
symmetrically on either side of the optic
axis of the lens so that the total angular
subtense of these red and green aper-
tures totals {/5. The area outside of the
red and the green apertures is used for
the blue image, that is, between //5 and
f/2.3. Narrow guard bands, which are
opaque, are inserted between each of
the aperture positions. These guard
bands customarily occupy approximately
10% of the total area of the aperture.

In order to calculate the size of the
apertures required at the first focal plane
of the objective lens of the densitometer,
it is necessary only to measure the focal
length of the objective lens. The aperture
width can then be calculated very simply,
since f-number = //w, where f is the
focal length of the objective lens and w
is the width of the aperture slot.

The second condition is that this aper-
ture be placed in the first focal plane of
the objective lens. This point can be
established on a conventional optical
bench with very little trouble. The
following example may not necessarily
apply to other densitometers of the same
model: The focal length measured for
this instrument was 52 mm. This corre-
sponds to an aperture width of 4.7 mm.
This aperture should be placed 1 mm
from the vertex of the first element of the
lens in order to be in the front focal
plane. It should be repeated that these
values apply specifically to the first
instrument modified and would not
necessarily apply to other models.
Later series of the instruments should
have focal lengths close to these values.

Testing the Optical System

It would be useful to measure the
effectiveness of this optical system in
analyzing the three separation images.
This can be done quite simply by replac-
ing the normal aperture slide with a
slide containing a narrow slit ( 1 mm).
for the aperture. A film containing a

REFLECTING
PRISM

APERTURE
SLIDE

OBJECTIVE
LENS

FILM SAMPLE

INTEGRATING
SPHERE

Fig. 3. Modified densitometer illumina-

tion system.

Brown, Combs and Smith: Densitometry of Embossed Kinescope Recording Film

‘
J
|

3

|

|

v

-0.3 -02 +0.1 +0.2 +03

Distance from optic axis (inches) *

Fig. 4. Measured density distribution about optic axis of densi-

tometer.

single separation exposure is then placed
in the densitometer and the small slit is
slowly moved across the focal plane of the
objective lens. Densities are read at a
great many positions of the slit. Since the
image of the slit is formed by the objec-
tive lens and lenticules in the plane of
the emulsion, this slit image moves
proportionately to the movement of the
slit in the aperture slide. If the film
sample contains only one separation ex-
posure, there will be little density in the
film except in the geometric area al-
lotted to this separation image. This is
illustrated by the microdensitometer
trace shown in Fig. 1. When this slit
image is outside of the geometric image,
the density will be low. When the slit
image moves into an exposed area, the
density recorded will increase. A series
of four exposures have been measured
in this fashion and are shown in Fig. 4.
These four film samples were exposed to
a red-separation image exposure, a green-
separation exposure, a_ blue-separation
exposure, and the same exposure given
to the red, green and blue separations to-
gether. The latter exposure corresponds
to the neutral exposure on the film.

Fig. 6. Westrex Densitometer with cover removed and aperture
plate in position.

Fig. 5. Aperture plate for Westrex Densitometer.

The average distributions of density
behind the lenticules for these four ex-
posures are presented together in Fig. 4.
The densities of the single-separation ex-
posures bear a marked resemblance to
the microdensitometer trace in the
earlier figure. The same quantity is be-
ing measured, though in two quite dif-
ferent fashions. The curves show that
the image is largely confined to the geo-
metric area provided for the separation
but that some light is spilled into the
adjacent areas. This spilled light results
in a loss of density in the primary image
and an increase in density in the adja-
cent areas. It is this loss in density that
causes the neutral exposure to have a
higher density than the same exposure
given to the individual images which
make up the neutral.

One of the differences between the
microdensitometer trace and the trace
obtained with the densitometer is the
density difference between the peak
density in the image and the density in
the adjacent areas beside the image.
This density difference is considerably
greater for the microdensitometer trace

‘than it is for the measurements in the

densitometer. This effect can be ex-

position for use.

plained since the density measured with
the Westrex is diffuse density, whereas
that measured with the microdensitome-
ter is close to specular density. In normal
use of the embossed film in a television
projector, the specular density is the
significant quantity; hence the larger
density difference shown with the micro-
densitometer trace is perhaps a closer
representation of the actual image ob-
tained in projection. Since diffuse den-
sity can be related to specular density by
multiplying it by the Q-Factor of the
film and optical system combination,
this does not represent a real handicap.

Shown at the top of Fig. 4 is the nor-
mal aperture size used for reading the
red- or the green-separation image.
The blue image is read by two apertures
of this same size, located symmetrically
on either side of the optic axis.

Dimensions of Aperture Plate

It would perhaps be useful as an ex-
ample to show the dimensions of the
actual aperture plate used. The aperture
plate, shown in Fig. 5, is designed to
read an image where the red and the
green separations subtend //10 on either
side of the optic axis and the blue image

Fig. 7. Westrex Densitometer with aperture plate and cover in

650 December 1956 Journal ofthe SMPTE Volume 65

2
”
2 8 ~
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y \
c
3 »
%
|
be
4

subtends the remaining aperture from
f/5 to {/2.3. The normal projection
guard bands equal to 10% of the open
area are inserted between these aperture
slots. The position of the aperture plate
relative to the optic axis is controlled by
the detents on one edge of the slide.
The large circular aperture at one end
of the slide permits normal operation of
the densitometer.

Only two rectangular slots are needed
to read the densities of all three separa-
tion areas. As the slide is advanced
across the focal plane of the objective
lens, the first detent stops it so that cne
aperture is positioned on the righthand
side of the optic axis and immediately
adjacent to it. The second detent stops
the same aperture on the lefthand side
of the optic axis, corresponding to the
second separation image position. The
third detent stops the first aperture on
the extreme lefthand side of the optic
axis, at which time the second aperture
is in position to let light pass through the
extreme righthand side. Light from these
two positions corresponds to the illumina-
tion required for the blue image. The
detents which orient the aperture plate
must be placed carefully relative to the
optic axis of the objective lens.

The most convenient place to mount
the aperture slide and slide holder in the
Westrex Densitometer is on a prism
holder directly above the objective lens.
The completed modification with the
aperture slide in this position is shown
in Fig. 6. For clarity, the cover of the
instrument has been removed. The slide
can be seen on the righthand side of the
prism mount. The instrument, with the
cover in place, is shown in Fig. 7. The
photographs indicate the mechanical
simplicity of the modification. '

Sensitometric Scales

A sample of the sensitometric scales
measured with the instrument is shown
in Fig. 8. The exposure from which
these images were obtained was made as
follows: An exposure intensity series was

given to the area corresponding to the
This

green-separation position only.

exposure was a normal sensitometric
scale with equal steps in log exposure.
No exposure was given to the red- or the
blue-separation positions. The film was
normally processed and then read in the
densitometer. The densitometer indi-
cated the density in the green-separation
pesition, and this curve is indicated by
the solid curve, “G,” in the figure. The
density in the red and the blue areas
was also read. These densities are
labeled ““R’’ and “B” in the figure. Al-
though no exposure was given in these
regions, some density has been produced
by light scatter and the other factors
mentioned previously. The density of
the green-separation position in a neu-
tral exposure is shown by the dashed
curve in the figure. The exposures given
in the green-only and neutral exposures
were identical. The loss of density shown
by the difference between the dashed
curve and the solid curve indicates the
amount of light scattered out of the
green image. In the case of the neutral
exposure, the light scattered out of the
green image is compensated for by light
scattered into the image by the adjacent
area exposure. In the green-only expo-
sure, no such compensation occurs,
hence an exposure loss from the image.
The resulting loss in density is shown in
the figure.

Sensitometric curves of this nature
are very informative in the analysis of
both the exposing and the projecting
conditions for embossed-film images.
If the aperture images are poor, there is
considerable contamination in adjacent
areas for exposure given to one of the
separation areas. This loss of image
separation will show up immediately in
the densitometry by an increase in den-
sity of the adjacent exposure areas and
in the density loss of the intentionally
exposed area. Similarly, images which,
upon densitometry, show good color
separation should show good color satu-
ration upon projection. If they do not,
the optics of the projection system should
be examined.

The ability to measure density in the

Brown, Combs and Smith: Densitometry of Embossed Kinescope Recording Film

Density

20
Log exposure

Fig. 8. Typical sensitometric curves of
neutral and green exposures.

separation images is fundamental to
satisfactory use of an embossed film.
This is particularly true if the optical
system in which the film is being ex-
posed and projected is of a new design.
There are many pitfalls in the design
of optical systems in which embossed
films are used. Only with some method
of adequate image analysis can the de-
signer know with certainty that his sys-
tem is functioning properly. It is hoped
that the present densitometer modifica-
tion will provide a useful method of im-
age analysis.

References

1. C. H. Evans and R. B. Smith, “Color kine-
scope recording on embossed film,”’ Jour.
SMPTE, 65: 365-371, July 1956.

2. W. R. J. Brown, “A rapid-scanning micro-
densitometer,” Jour. SMPTE, 63: 147-150,
Oct. 1954.

3. J. G. Frayne and G. R. Crane, “A precision
integrating-sphere densitometer,” Jour. SMPE
35: 184-200, Aug. 1940.

Discussion
Louis Meeussen (Gevaert Co., Antwerp, Belgium):

Why is the scattering of light into the red zone

different from that into the blue one?

T. Gentry Veal (who read the paper, Eastman
Kodak Co.): When the exposure is made, through
the green printing aperture only, for example,
there is one blue sector which receives very little
scattered light. The other blue zone will receive
approximately the same amount of scattered
light as the red zone from this single exposure.

4
Y 651

Replaceable Pole Tip Caps for

CinemaScope Magnetic

Reproduce Heads

Ring-type magnetic recording and reproducing heads are contacted by the abrasive
medium, and hence their useful life is shortened by wear, replaceable pole tip cap

consists of a pair of brass holders in which the laminated tips of the cores are plas-
ticized. The cap is fastened to the main housing assembly by means of two 1-72
screws, and locating pins are employed to assure correct azimuth on the part of the

precision-aligned pole cap.

magnetic recording and
reproducing heads are contacted by
the recording medium, and hence their
useful life is shortened by a wear process.
In this respect, light-scanning and photo-
electric systems such as those used in
theater soundheads are not subjected
to such contact effects. Magnetic heads,
therefore, resemble mechanical trans-
ducers such as phonograph styli, which
are similarly worn away during the
recording and reproducing processes,
and must be replaced periodically.

The idea of employing a magnetic
recording head with a replaceable record-
ing tip, or cap, has no doubt occurred to
many who have been engaged in the
field of magnetic recording. There are
even some patents describing such
means.

It is the purpose here to describe some
replaceable pole cap constructions which
the author has studied or has built
before the present design was developed.
Figure 1A is a diagram of one type of
replaceable pole cap consisting of two
“cores” soldered to a brass rod in such
a way that the “legs” can be slid into a
mu-metal or Permalloy yoke which com-
pletes the magnetic circuit. To avoid
high frequency losses, the “cores” can-
not be much thicker than 0.006 in.
In other words, a core is a single longi-
tudinal lamination, bent at one end to
form the recording tip, and left styaight
for the remainder so that it can /be in-
serted into a magnetic yoke. However,
because the depth of the front gap pole
face is only 0.006 in., such a replaceable
pole cap has to be replaced relatively
often, and requires a good friction lock
between leg and yoke to avoid displace-
ment difficulties between the two. It
might be said that these longitudinal
laminations can be built up in layers,
so that instead of a 0.006-in. front gap
pole face depth, these depths become
multiples of these dimensions (0.012

Presented on October 10, 1956, at the Society’s
Convention at Los Angeles by Michael Rettinger,
RCA Engineering Products Div., Radio Corp.
of America, 1560 N. Vine St., Hollywood 28.

(This paper was received on August 27, 1956.)

December 1956 Journal of the SMPTE

By MICHAEL RETTINGER

Types of replaceable pole caps.

Figure 1A

in., 0.018 in., ete.). However, in the
life of such a head there must in-
variably come a time when a lamination
has worn through and the recording
medium rides not on a magnetic material
but on a layer of cement or solder. In
other words, it is difficult with such a
multiple-layer cap to provide continu-
ously satisfactory performance.

Figure 1B shows another possible con-
struction for a replaceable pole cap. The
recording tip is cemented to the main
core section in one manner or another,
either by soldering or by using thermo-
setting resins. However, such a construc-
tion is afflicted with two very serious
shortcomings. First, there exists so-called
secondary gaps at the joints between
the pole tip and the main core which
give rise to undesirable low-frequency
response variations. Second, the (solid)
pole tip must again be made very thin
to avoid high-frequency losses.

Figure 1C shows still another possible
replaceable pole tip construction. Here,
the pole face depth can be made any
dimension within reason, for example,
0.050 in., but the secondary gap effect
cannot be avoided. Also, the pole tip
exchange cannot readily be made in the
field because the construction requires
disassembly and reassembly at the factory
for the purpose of replacing the worn
part. This is necessary because the pole
faces, after being applied to the main
core section, must be made flat, a spacer
must be placed between them and the
entire tip assembly must be ground and
polished at the place where the recording
medium contacts the recording tip.

| BRASS BAR \
CORE 006

Figure 1B

Figure 1C

Figure 2A shows another tip, essen-
tially a single lamination core tip, which
has been kept straight for the purpose
of ecenomy and for securing a tight
friction lock between pole cap and the
main core section. In this case, the cor-
ners of the replaceable pole cap give rise
to violent low-frequency response varia-
tions because of a secondary gap effect
similar to that produced by the con-
struction shown in Figs. 1B and 1C.
To avoid this shortcoming, concave
sapphire spacers might be applied to
the ends of the cap to introduce a varying
air space between the extreme corners
of the cap and the recording medium
and a pressure roller used to force the
film into the recording head cavity as
shown in Fig. 2B. This construction,
besides being costly, is cumbersome and,
in the case of the stiff motion-picture
film, practically impossible to use, al-
though thin tape could possibly be
pressed into the hollow of the cap.

The present construction (Fig. 2C)
avoids all the difficulties associated with
solid pole pieces, such as secondary gaps,
pressure rollers, factory disassembly and
reassembly, by utilizing a sturdily built
laminated pole tip assembly which
can be changed by anyone in the field,
with the aid of a screw driver. Locating
pins inserted in the main or basic cluster
circumvent alignment problems when
the replacement cap, with its corres-
ponding locating pin holes, takes the
place of the worn unit. The front gap
pole face depth can be of the same
order as that of the laminated head used
heretofore. The main part of the pole

Volume 65

~

LAMINATED
PERMALLOY

LAMINATED

PERMALLOY FERRITE
REPRODUCE RECORD
HEAD HEAD

Fig. 2A. Single lamination core tip.

cap, which consists of two solid machined
brass holders, can be salvaged after the
core tips have been worn away, and may
be used again if desired.

Figure 2D shows the essentials of the
construction of the present replaceable
pole caps. The laminated Permalloy,
mu-metal or Alfenol core tips are plasti-
cized in brass holders with a special
thermosetting casting resin. The front
gap pole faces are then lapped as a unit
on a diamond lap to assure that all faces
are in the same plane. When the perti-
nent front gap spacers have been inserted
between the two halves of the pole cap,
the pair is screwed together.

The construction of the main cluster
follows the method of fabrication em-
ployed with our regular magnetic
head clusters, except that 0.200 in.
is ground away from the core tips *o
provide a flat surface for the replaceable
pole tip cap.

Because two additional air gaps are
introduced into the construction, the
- reluctance of the magnetic circuit is
increased. To compensate for the low-
ered inductance (as produced by the
increased reluctance), additiona! turns
of wire are required on the cores. The
slightly lowered 1000-cycle sensitivity
was corrected by employing a slightly
thicker front-gap and a slightly thinner
back-gap spacer. Although the front-
gap spacer used previously was 0.0003 in.
and the new front-gap spacer was made
0.0005 in. thick, this spacer thickness
increase had no effect on the high-fre-
quency response of the unit since the
film speed is relatively high (90 ft/min).
Actually the effective gap before was in
the order of 0.0007 in., while the new
gap length is in the order of 0.0010 in.

Difficulties were at first experienced
in the use of this type of head as a re-
cording head because of increased bias
current requirements. This was undoubt-
edly due to the two additional air gaps
contained in the construction. The sur-
faces of these gaps become work-hard-
ened and thereby represent a relatively
high reluctance to the 68-kc bias flux.
The extra magnetomotive force required
for the flux to be able to bridge these
gaps must be made up by increasing the

Rettinger:

Fig. 2B. Pressure roller forcing film
into recording head cavity.

be we

SAPPHIRE SHOE

Fig. 2C. Construction of ‘the present
replaceable pole cap.

Fig. 2D. CinemaScope Magnetic Reproduce Cluster with replaceable pole cap.

magnetizing force, in this case the bias
current.

This shortcoming was corrected by
mounting the laminated Permalloy pole
tip cap on a substructure of solid fer-
rite cores instead of laminated cores.
The lower bias current required by such
a unit is in all probability due to the
lower reluctance of the cores themselves,
because the eddy current losses of ferrite
are relatively small, and may also be
due to the two additional gap surfaces
not having become work-hardened, be-
cause ferrite is not a metal but a sin-
tered ferrous oxide.

Acknowledgments

The author wishes to give credit to
the competitive stimulus provided by
Ray Warren, of the Advanced Develop-
ment Group of RCA, Camden, N.J.,
who worked on a magnetic head with
a replaceable pole cap using solid Alfenol
tips; and especially to W. L. Tesch,
Manager, Film Recording Equipment
Planning, who showed so much interest
and encouragement in the project.

Discussion

R. A. Isberg (Ampex Corp., Palo Alto, Calif.):
Can you comment about the wearing qualities
of Alfenol compared to Permalloy?

Mr. Rettinger: There’s no question but that
the Alfenol will last considerably longer than
laminated Permalloy. The laminated Alfenol
tip will last longer than the laminated Permalloy
tip, but the difficulty has been to obtain lami-
nated Alfenol because it is so extremely hard to
roll; so far it has only been available in experi-
mental samples. What the exact wear ratio is
I’m not sure. So as far as this laminated type of
cap construction is concerned it makes little dif-
ference what pole tip material we use, Permal-
loy or Alfenol — but with replaceable pole cap
constructions which consist of solid pole tips,
it becomes very important what material is used.

Lloyd Goldsmith, (Warner Bros.): Is it antici-
pated that this replaceable pole cap tip con-
struction might be applied and furnished with
your single-track, three-track perhaps, and six-
track heads?

Mr. Rettinger: Yes, it is practical to employ it
with any type of magnetic head. We have used
it so far chiefly for CinemaScope reproduce
heads of which we have several hundred in the
field, and which has worked out very well.
Whether we shall employ it also for recording
heads for studio installations is something that
shall have to consider.

Replaceable Pole Tip Caps for Magnetic Reproduce Heads 653

ROLLER
FILM
|

Instructions for SMPTE
Reg - 16— Registration Test Film

Tuis FILM was developed to provide in a single test film of high
accuracy several quantitative visual tests that have always
been difficult to perform. They are as follows:

Projector steadiness ;
Projector aperture alignment;
Projector shutter adjustment (travel ghost) ;
Projector framing accommodation ;
Projector focusing;
Optical printer alignment;
Optical projector focusing ;
Contact printer resolution;
Contact printer weave;
. Contact printer double-exposure alignment;
. Contact printer (step) steadiness;
. A frame of this film may be used in a camera aperture
for aligning a title stand;
. By laying the scale on this film emulsion to emulsion on
a sound record, its location may be measured.

If the film is projected to 30 X 40 in. it will be enlarged 100
times. Since the |-mil scale is 1/10 of an inch long on the’ _ Detail of the frame content.

film, it becomes 10 in. long on a picture of 30 X 40 in.

Geo W/ u-®@-es

CORRECTION: The above shows the content of a frame of the REG-16 Test Film which is a positive print having a black background
— contrary to the illustration published on p. 436 of the August 1956 Journal.

654 December 1956 Journalofthe SMPTE Volume 65

>
\
|
2.
4. YW |
6
| 7. |
8.
9.
10
11
12
| \\)
|

.163

PROJECTOR APERTURE
CAMERA APERTURE
404X292

84

050

.414

Dimensions of REG-16 — Registration Test Film. Aperture dimensions are in accordance with PH22.7 and PH22.8.

(1) The test film is a positive print having a black back-
ground with all copy white or transparent. The film stock used
has high resolution and has been accurately perforated both
edges one frame interval at a time so that the steadiness of
each frame will be in respect to its perforation.

(2) The dimensions were obtained from present standards
and adjusted to units of 1 mil and either represent the ideal
condition or an average one in practice. For instance, the out-
side rectangle represents the camera aperture and the rec-
tangle just inside, the projector aperture. The inside line should
project on the screen in all projectors if designed according to
SMPTE standards. If the camera aperture line should show
in projection it would present an extremely large projector
aperture.

(3) Resolution targets are spaced one in the center, four
equidistant from the center and one in each of the four corners.
The outside diameter of target on the film is 50 mils and will
fill the area covered by an average microscope using a 10X
objective. The original drawing of the target was laid out to
an accuracy of 1 mil at 200 times size, i.e., 20 in. on the drawing
reduces to 50 mils on the film.

(4) The white blocks are 10 mils square and will quickly
indicate travel ghost caused by incorrect shutter adjustment,
They also provide a quick check on the ability to frame above
and below center position.

(5) The vertical rows of numbers 20, 30, etc., refer to lines
per millimeter in the concentric rings of the resolution targety
and also provide title size copy for rough focusing.

(6) The scales provide detailed copy on the chart and repre,
sent thousanths of an inch. These are helpful when film ig
double exposed in a printer to check registration.

(7) The copy on either side of the center target provides
more fine detail and explains resolution targets.

(8) The lines adjacent to the sprocket-hole outline provide
a means for accurately adjusting the image of the master chart
to the film while being photographed.

(9) The triangular areas in the centers of the vertical and
horizontal frame lines provide a means of measuring the
amount of jump and weave and as a gauge for centering the
film in the aperture laterally. Each line is 1 mil thick and
spaced 1 mil. Count the white lines as 1 mil and the space
between as 1 mil. Two white lines and a space total 3 mils op
0.003 in.

December 1956 Journal ofthe SMPTE Volume 65

a
4
7115
° °
- w—- - - -
|
(ww,
. a
050 256
655.

Two American Standards,
PH22.34, .102 — 1956

Published here are American Stand-
ards PH22.34-1956, Dimensions for
35mm Motion-Picture Film, BH-1870,
and PH22.102-1956, Dimensions for
35mm Motion-Picture Film, CS-1870,
which were approved by the American
Standards Association on October 10,
1956.

PH22.34, a revision of Z22.34-1949,
and PH22.102 had their trial publication
in the November 1955 Journal. Subse-
quently, several editorial modifications
of both standards were proposed and
approved and are incorporated in these
final drafts. These include a new title,
an improved method of diagramming
dimension G, a limiting scope, formal
numbered specifications, two explana-
tory notes and a slight revision of the
appendix.—Henry Kogel, Staff Engi-

neer.

ee

2

Page 2 of 2 pages

for all film dimension standards: Each title pro-
vides an indication of the film width, the perfora-
tion pitch (without the decimal point) and the

perforation shape (BH, KS, DH or CS) or number

of rows of perforations (1R, 2R or 4R), depending

on which is the significant factor.

application of a nomenclature system developed

2. The title of this standard wos established by the

the life of the film. The change is generally uniform

in that the dimensions throughout a roll.

35mm Motion-Picture Film, BH-1870, PH22.34-1956, but is included

its use.
of film

and tolerances are for film immediately after per-

The dimensions given in this standard represent the

Appendix
focilitete

(This
to

The uniformity of pitch, margin and hole size (Dimen-

sions B, C, D and E) is an important variable affecting
steadiness.

ond dies th Ives are made to

The p

bly Her than th given, but

since film is a plastic material, the dimensions of the

from one

d to

Variations in these dimensions from roll to roll are of
little significance Ap iati:
shrink or swell due to loss or gain in moisture content sprocket hole to the next. Actuolly, it is the maximum
or can shrink due to loss of solvent. These changes variation from one sprocket hole to the next within
invariably result in changes in the dimensions during any small distance that is important.

slit and perforated film never agree exactly with the
dimensions of the slitters, punches and dies. Film can

PH22.34-1956

Qa
|

O

and
motion-
perfora-

35mm
type
tion and a perforation pitch of 0.1870 in.

picture film with a Bell & Howell

Dimensions for
35mm Motion-Picture Film, BH-1870

AMERICAN STANDARD

Scope
1.1 This standard specifies the cutting
perforating dimensions of the i

1.2 This film is used mostly as camera orig-

inal or negative film.

1.3 Dimensionally, this standard differs from
American Standard Dimensions for 35mm
Motion-Picture Short-Pitch Negative Film,

PH22.93-1953, only in the values of B and L.

2.
2.1 The dimensions shall be as
diagram and Sable and refer to
mediately after cutting and perforating.

ooo

8
i HHHHHH 4
| |
wv
socooo
HHHHHH

L388

Dimensions

a

2.2 Dimension H is a calculated value for a
dimension not measured routinely in produc-

tion.

2.3 Dimension L represents the length of any

100 consecutive perforation intervals.

*Universal Decumal Classsheation

ot,

Approved October 10, 1956 by the A

Sponsor: Society of Motion Picture and Television Engineers

December 1956 Journal of the SMPTE Volume 65

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657

December 1956 Journal of the SMPTE Volume 65

Hin

-
news and ==

81st Convention Program

The Spring Convention, in Washington,
will be distinguished by the variety and ex-
tent of the topics presented rather than by
the exploration of a single theme, attempted
often in the past. The Convention’s new
look represents gradual evolution and inten-
sification of organization by subject areas.

For several years, television, high-speed
photography and screen brightness have
intermittently been the responsibility of
subject or topic chairmen; now there are
ten topic chairmen. The organization of
Convention committees and the distribu-
tion of responsibility have been changed to
conform with a logical pattern of planning,
with the aim of contributing to the success
of the total Convention structure. For the
81st Convention:

Program Chairman: Joseph FE. Aiken, 116
North Galveston St., Arlington 3, Va.

TOPIC CHAIRMEN

Audio-Visual Uses of Motion Pictures
and Television: John Flory, Advisor on
Nontheatrical Films, Eastman Kodak
Co., 343 State St., Rochester 4, N. Y.

Cinematography: ./ohn A. Maurer; JM De-
velopments, Inc., 116-118 West 29th St.,
New York 1, N.Y.

Film Projection and Viewing: Herbert E.
Behrens, 31 Sheridan Ave., Metuchen.
N. J.

Theater Operation: Fred E. Aufhauser,
Projection Optics Co., Inc., 330 Lyell
Ave., Rochester 6, N.Y.

Industry Milestones: Don G. Malkames, 7
Plymouth Ave., Tuckahoe, N.Y.

Instrumentation and High-Speed Pho-
tography: John H. Waddell, Fairchild
Camera and Instrument Corp., 88-06
Van Wyck Blvd., Jamaica 1, N.Y.

Laboratory Practice: Garland C. Misener,
Capital Film Laboratories, Inc., 1705
Fairview Ave., N.E., Washington 20,
D.C,

Sound Recording and Reproduction:
Jack C. Greenfield, 3201 Park Dr., S.E.,
Washington 20, D.C.

Standards and Standardization: EFilis W.
D’ Arcy, Box 1103, Ogden Dunes, Gary,
Ind.

Television: N. Harmon, Vice-Presi-
dent for Engineering, Westinghouse
Broadcasting Co., 122 East 42nd St.,
New York 17, N.Y.

Author’s Forms are available from the
above, from any member of the Papers
Committee (p. 7 of the April 1956 Member-
ship Directory), or from the Regional Chair-
men.

REGIONAL CHAIRMAN

Those formerly calied Vice-Chairmen of
the Papers Committee are now Regional
Chairmen, Papers Committee. This com-
paratively small change was made chiefly
for clarity. A prospective author can be
expected to understand the difference in
function between a Topic Chairman and a
Regional Chairman, either of whom may
approach him to solicit a paper. The roster
of Papers Committee Regional Chairmen
for 1957-58 as announced by Glenn E.
Matthews, Editorial Vice-President, is as
follows :

Joseph E. Aiken — Washington area — 116
N. Galveston St., Arlington 3, Va.

Ben Akerman — Atlanta area — 2624 Che-
shire Bridge, Rd., N.E., Atlanta 5, Ga.
Herbert E. Farmer — Hollywood area —
7826 Dumbarton Ave., Los Angeles 45,

Calif.

C. L. Graham — Rochester area — 500
Thomas Ave., Rochester 12, N.Y.

R. A. Isbere — San Francisco area — 2001
Barbara Dr., Palo Alto, Calif.

Everett Miller—New York area — 94
Rossmore Ave., Bronxville 8, N.Y.

Tra L. Miller, Jr., — Dallas-Ft. Worth area
— Miller’s Visual Aids, 519 Pennsyl-
vania Ave., Ft. Worth, Tex.

C. E. Heppberger — Chicago area — 231 N.
Mill St., Naperville, Il.

Rodger J. Ross —Canadian area — 784
Duchess Dr., Applewood Acres, Port
Credit, Ont., Canada

Deane R. White — New Jersey/Philadel-
phia area — E. I. du Pont de Nemours
& Co., Parlin, N.J.

Looking six months further ahead — the
82d Convention, to be held at Philadelphia,
will be a program under the chairmanship
of Deane R. White, whom we are most for-
tunate to have for this convention in a new
location.

The program of the motion-picture short sub-
jects which will introduce each technical
session of the 81st Convention will be ar-
ranged by Ethan M. Stifie, Eastman Kodak
Co., 342 Madison Ave., New York 17, N.Y.

EXHIBITS

As a location for shows and exhibits
Washington is a natural, and the wide-
spread interest that exists in various govern-
ment departments in the kind of profes-
sional equipment usually shown at SMPTE
conventions makes this an especially good
opportunity for exhibitors. Walt Trimby,
the Exhibit Chairman for this convention,
is arranging with the Shoreham for some
very attractive space and expects to have a
floor plan and full information out in tue
mail to potential exhibitors about the time
that this issue of the Journal appears.

Space at these exhibits is allocated strictly
in accordance with the order in which
applications are received. Several such re-

reports

quests are already in, and anyone who
wants to be sure of getting a bid in even be-
fore the printed forms are received should
contact Walt immediately. His address is:
Walter W. Trimby, SMPTE Exhibit Chair-
man, 1627 Preston Rd., Alexandria, Va.

Special interest has been aroused for this
Convention by a tentatively scheduled
group of papers under the general heading
of Audio-Visual Uses of Motion Pictures
and Television. This portion of the program
is expected to encompass such subjects as
the economic impact of the audio-visual
field, variously elaborate or simple projec-
tion equipment and materials, new equip-
ment and closed-circuit television.

The projected session on Industry Mile-
stones will include a description and intro-
duction for the Motion Picture Collection
at the Smithsonian Institution which mem-
bers can visit during the Convention to see
the collection which includes much equip-
ment.

An important omen for the 81st Con-
vention is that many of those listed above
have been at work for months, working out
the format and getting tentative commit-
ments for papers and demonstrations.

Prospective authors who are not certain
about choosing a Topic Chairman or Re-
gional Chairman from the above, should
write direct to Program Chairman Joseph
E. Aiken. Author’s Forms are due back in
the hands of those responsible for the
Convention by or before March 1; and the
completed manuscript must be submitted
to the Society’s Editor before March 29.—
Bernard D. Plakun, Papers Committee Chair-
man.

Education, Industry News

Two new education courses, co-sponsored
by the SMPTE and the IATSE, will be
given through New York University be-
ginning in February 1957. These courses
were planned by two subcommittees of the
Society’s Education Committee — the
Sound Recording Subcommittee, under the
chairmanship of Edgar A. Schuller of De-
Luxe Laboratories; and the Laboratory
Practice Subcommittee, under the chair-
manship of James W. Kaylor of Movielab.

A twenty-week course in Elements of
Motion Picture Sound Recording, designed
to improve the technical ability of persons
now actively engaged in sound recording,
will cover basic principles of electricity,
sound and acoustics; present day recording
methods, materials, equipment and _ per-
sonnel; production and maintenance tech-
niques and procedures; and factors govern-
ing sound recording quality. Classes will
meet on Wednesday evenings from 7:30 to
10:00 and will be taught by leading men
in the sound recording field. Tuition, which

658 December 1956 Journal of the SMPTE Volume 65

STEREOPHONIC SOUND" IS BETTER

THAN ANY SINGLE CHANNEL SOUND

Give your customers the best

Get the full dramatic brilliance of sound of today’s
top-rated motion pictures!

The new Westrex Stereophonic equipment repro-
duces the full range, tone and quality recorded on the
film. This new equipment is simpler in design and
cheaper to install and maintain. Prices are 5% to 30%
lower than comparable 1955 equipment.

FOR THE BEST in multi- or single channel,
magnetic or photographic sound systems

THE WESTREX
© WESTREX Standard
e WESTREX Economy

*Three channel, four channel, or six channel

Westrex. Corporatio

=
‘
|
December 1956 Journal of the SMPTE Volume 65 659} Bi

will ultimately depend on the number of
registrants, will probably be between $30
and $50.

The course in Motion Picture Laboratory
Practice wil] run for eighteen weeks and will
cover basic photographic processes, funda-
mental optics, sensitometry, motion-picture
developing and printing, chemical and
quality control, and the processing of
color films.

Applications for these courses should be
sent to SMPTE headquarters and should
cover name, address, education, age, pres-
ent position, experience in sound recording /
laboratory practice, and other allied ex-
perience. Final information on instructors,
tuition, and date and place of registration
will be sent to those applying.—S.G.

The Rochester Institute of Technology
has added a course major to the Depart-
ment of Photography. Candidates for the
degree of Bachelor of Fine Arts may major
in Professional and Applied Photography
beginning with the next school year. The
department formerly awarded degrees only
in Photographic Science and Illustrative
Photography.

UCLA’s closed-circuit television system
was used to permit students in the Univer-
sity’s Medical Center Hospital to watch the
Homecoming parade. Rudy Bretz, head of
the school’s Television-Radio Division,
produc d the broadcast assisted by a crew
of 15 students. This production was one in a
series of remote telecasts planned by Bretz
for student training. Although vidicon
cameras were used in this outdoor night
telecast, it is reported that no more lighting
was used than would have been necessary
for standard image-orthicon pickup.

A list of 145 films on Atomic Energy and
related subjects is contained in the October
1956 issue of the Scientific Film Review, pub-
lished by the Scientific Film Association,
164 Shaftesbury Ave., London, WC2. The
information is arranged alphabetically by
film title and includes a description of each
film. Copies are available from the pub-
lisher at 3/6d each.

Electronic News, a weekly newspaper for
the electronics industry begins publication
on January 21. The new publication is
edited for management and engineers.
Introductory subscription rate is $2.00 for 3
years or $1.00 a year. Orders may be sent to
Fairchild Publications, 7 E. 12th St., New
York 3.

The National Audio-Visual Association
has moved its headquarters from Evanston,
Ill, to Fairfax, Va. The Association has is-
sued the 3rd edition of the Audio-Visual
Equipment Directory. The 197-page di-
rectory reflects the expansion taking place
in the industry and in all audio-visual ap
plications. Not only are there more equip-
ment items, but changes in design and the
addition of new sources of supply are sig-
nificant of progress throughout the industry.
The editor of the new directory is Robert
J. Schmidt, NAVA Director of Services,
and the associate editor is Henry C. Ruark,
Jr., Associate, Audio-Visual Center, In-
diana University.

Something unusual in SMPTE Section
activity was witnessed in November when
the Chicago Section held its annual
Regional Meeting in Detroit. Over 200
members registered for the sessions which
were held on Friday and Saturday, Novem-
ber 9 and 10, in the headquarters of General
Motors Photographic.

The meeting was a grand success tech-
nically and socially. Nine top-notch papers
were presented during the meeting, cover-
ing all phases of motion-picture production.
General Motors was host at a cocktail
party preceding dinner on Friday night.
A total of 155 people attended the dinner.

Much of the success of the meeting was
due in no little part to the efforts of Bill
Smith, Lakeside Laboratory, Gary, Pro-
gram Chairman for the Chicago Section;
Jim Bostwick and Mike Omalev of General
Motors Photographic, local arrangements
chairmen, and the nine speakers them-
selves.

Equipment available for the meeting in-
cluded two 16mm arc projectors, two 35mm
arc projectors, lantern slide projectors and
2 X 2 standard and wide-screen.

Twenty-nine members from Chicago
were transported to Detroit on a special
New York Central excursion. They were
met by chartered bus in Detroit and car-
ried to the Park Shelton Hotel where rooms
had already been assigned to each person.
Several other out-of-town members ar-
rived by plane and private car.

The award for attendance goes to the
University of Indiana which not only had
three members of its Audio-Visual Staff

present, but also 18 foreign exchange
students. It was learned from Warren
Stevens of the Indiana Audio-Visual Center
that these students will return to their re-
spective countries and be involved in the
production of educational films.

Papers included ‘New Techniques in
Wild Life Photography,” Mort Neff, pro-
ducer of the TV show Michigan Outdoors;
“The Bi-Matic Projector,” John Campbell,
Jam Handy; “High-Speed Photography
Instrumentation,” Richard Painter, Gen-
eral Motors; ““A New Intermediate Positive
Duplicate Negative System,” Daan Zwick,
Eastman Kodak; **A Wide-Screen Color
Photographic Report from Russia,” Lloyd
Thompson, The Calvin Company; “Edit-
ing }-Inch Tape for Lip Sync Recording,”
Gordon Ellsworth, General Motors; ‘“‘Prob-
lems of the Small Producer,” Ray Balousek,
Producers Color Service; “New 16mm
Color Camera Films,” William Metzger,
Ansco; and “‘A New Continuous Contact
16mm Color Printer,’ Paul Ireland,
E.D.L. Co.—Ken Mason, Chairman, Cen-
tral Section; c/o Midwest Div., Motion-
Picture Film Dept., Eastman Kodak Co.,
130 N.E. Randolph Dr., Chicago 1.

A meeting of the Officers and Managers
of the San Francisco Section was held Octo-
ber 4 at the Tokyo Sukiyaki at Fishermans
Wharf, San Francisco. Officers and Man-
agers for the coming year are: Chairman,
R. A. Isberg; Secretary-Treasurer, Werner
Rhuel; Managers for a 2-year period, Lee
Berryhill, W. A. Palmer, W. E. Evans;
Managers for a 1-year period, Harry Jacobs
Ross Snyder, Walter Ball. The meeting was
attended by E. M. Stifle, Sections Vice-
President, who described the policies re-
lating to section organization and adminis-
tration.—R. A. Isberg.

The San Francisco Section met October 23
at Ampex Corp. headquarters, Redwood
City, Calif. R. J. Tinkham. Manager.

Speakers at the Detroit Regional meeting: seated, left to right, are: Richard O. Painter,
General Motors; John Campbell, Jam Handy; James Bostwick, General Motors; and
standing, left to right: Ken Mason, Eastman Kodak; Ray Balousek, Producers Color
Service; Daan Zwick, Eastman Kodak; Lloyd Thompson, The Calvin Company; Gordon

Ellsworth, General Motors; and Bill Smith, Lakeside Laboratory.

660 December 1956 Journal of the SMPTE Volume 65

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December 1956 Journal ofthe SMPTE Volume 65 661

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Audio Custom Eng., Ampex Corp., ad-
dressed an audience of 40 persons on “The
Solution to Some Problems of Making
Master Tapes.”” R. H. Snyder, Manager,
Video Tape Recorder Sales, Ampex Corp.
gave a “Progress Report on Video Tape
Recording.”” The Progress Report sum-
marized the information presented at the
SMPTE Fall Convention. The paper is
recorded and is available to other sections.
—R. A. Isberg, Secretary-Treasurer; Con-
sulting Television Engineer, 2001 Barbara
Dr., Palo Alto, Calif.

The Washington D.C. Section held its
first meeting October 22 in the General
Services Building Auditorium with an

attendance of 200. The speakers were
Walter D. Goldsmith, Ampex Corp., Red-
wood City, Calif., who presented a paper on
“The Modulation System of the Ampex
Videotape Recorder” ; and John A. Maurer
President, JM Developments, Inc., New
York, who spoke on “Developmental Pos-
sibilities in 16mm Projection Equipment.”
E. M. Stifle, SMPTE Sections Vice-Presi-
dent, attended the meeting and spoke
briefly on the history and growth of the
Society and described the highlights of the
80th Convention. Chairman of the new
Section is Keith B. Lewis. Members of the
Board of Managers are: James M. Barker,
Howland Pike, Nathan D. Golden, Jack C.
Greenfield, Philip M. Cowett and Watson
P. Dutton.—James A. Moses, Secretary-

Seasons Greetings

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The Rochester Section met October 27 at
Shelly Films, Ltd., Toronto, Ontario,
Canada. The speakers were Roger J.
Beaudry, Shelly Films Ltd., Toronto;
Chester E. Beachell, National Film Board,
Montreal; Edwin C. Fritts, Eastman
Kodak Co., Rochester, N.Y.; N. H. Grover,
Canadian Broadcasting Corp., Montreal
(who read a paper prepared by Stanley
Wilson, C.B.C., Montreal); and Richard
C. Gearhart, Eastman Kodak Co. Titles
of the papers presented (in that order) are:
“16mm Magnetic Striping Applications,”
“National Film Board Sprocketape Mag-
netic Recorder,” ‘Magnetic Sound Re-
production With Eastman Projectors,
Model 25 and Model 250,” ‘‘Application
of Magnetic Sound in TV at C.B.C.,”
“Use of Kodak Pageant Projectors for
Producing Lip Syne Sound.” Rodger J.
Ross of C.B.C., Toronto, acted as chairman
of the meeting.

This meeting is the first of the Rochester
Section to be held outside the Rochester
area. Approximately 100 members and
guests were present. About 50 persons at-
tending were from the Toronto area, about
20 from Rochester and the remainder from
Montreal; London, Ontario; Buffalo;
Ottawa; Boston and Chicago.—G. T.
Negus.

Ralph M. Evans addressed The Rochester
Section on “Sharpness and Contrast in
Projected Pictures’? November 29 at the
George Eastman House, Rochester, N.Y.
Mr. Evans is Director of the Color Tech-
nology Division of Eastman Kodak Co.
He had previously presented his paper at
the Society’s Fall Convention at Los
Angeles. Approximately 60 members and
guests attended the section meeting.—
G. T. Negus, Secretary-Treasurer, c/o
Eastman Kodak Co., Kodak Park Works,
Bldg. 65, Color Technology Div., Rochester
4, N.Y.

The Hollywood Section met November 20
at the Paramount-Sunset Corp. Studios,
Hollywood. An audience of 345 heard Phil
Adamson, Senior Staff Engineer, Hughes
Systems Development Laboratories, speak
on Elements of Automation. Panel mem-
bers for the inter-panel and open discussion
were: N. L. Simmons, Eastman Kodak
Ce., moderator; John Livadary, Columbia
Pictures; Harlan L. Baumbach, Unicorn
Engr. Corp.; L. B. Abbott, 20th Century-
Fox; Gordon E. Sawyer, Goldwyn Studios;
Sidney P. Solow, Consolidated Film In-
dustries; and Ub Iwerks, Walt Disney Pro-
ductions. A color film showing the use of
automation in the Hughes Aircraft Co.
supplemented Mr. Adamson’s address.—
John W. DuVall, Secretary-Treasurer, c/o
E. I. du Pont de Nemours & Co., 7051
Santa Monica Blvd., Hollywood 38.

The Dallas-Fort Worth Section met No-
vember 27 in the Banquet Room of
Chantly’s Resturant, Dallas. Nineteen
members and guests attended. Jack Frazier,
President of International Electronics Corp.
gave a demonstration of hi-fidelity sound
reproduction from the Frazier-May
speaker. Phillip Wygant, TV Production

i
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4
New York's new Coles
i 662 December 1956 Journal of the SMPTE Volume 65

Supervisor of Station WBAP-TV, Fort
Worth, gave an address on color TV
lighting.—R. K. Keitz, Secretary-Treasurer,
7123 Westbrook Lane, Dallas.

New Members

The following members have been added to the
Society’s rolls since those last published. The
designations of grades are the same as those
used in the 1956 MemBersuip Directory.

Active (M) Associate (A) Student (S)

This is the fifth list of New Members supplementing
the April Journal, Part II, Directory.

Albright, Robert Frank, Medical Photog.,
Eli Lilly Lab. for Clinical Research. Mail:
2343 N. Webster Ave., Indianapolis 19, Ind.
(A)

Bell, Howard R., Vice-Pres. Sales, Mole
Richardson Co., 937 N. Sycamore, Hollywood
38. (M)

Berzins, Vallis, Asst. Cameraman, Herbert
Kerkow, Inc. Mail: 24 Timber Rd., Glen
Cove, N.Y. (A)

Birns, Jack, Co-Owner, Birns & Sawyer Photo
Supplies, 8910 Santa Monica Blvd., Los
Angeles 46. (A)

Booth, Walter W., Jr., TV Techn., WPIX-TV.
Mail: 201 E. 39 St., New York. (A)

Bratton, Orley John, TV Supvr., USAF.
Mail: Box 308, Edwards, Calif. (A)

Brown, Frank Albert, Techn. Supvr., Color-
vision, Inc., 6061 W. Third St., Los Angeles.
(M)

Burleyson, Garth, Mot-Pic Recordist, Capital
Film Labs. Mail: 8207 17 Pl, Aldelphi,
W. Hyattsville, Md. (A)

Buss, John P., Film Techn., General Film
Labs. Mail: 11663 Oxnard St., N. Hollywood.
(A)

Byer, Maxwell Theodore, Techn. Dir., Byer
Industries Pty. Lid., 8 Dorcas St., S. Mel-
bourne, Vict., Australia. (M)

Canter, Edward Harrison, Recording, Sound.
Techrisonic Studios, 1201 Brentwood, St.
Louis 17, Mo. (A)

Carroll, Thomas Joseph, Production Manager,
Lewis & Martin Films, Inc. Mail: 7421 Coles
Ave., Chicago 49, (A)

Cartwright, Vern William, Photog., Free-Lance.
1048 Toneight Way, Sacramento, Calif. (M)
Chang, Kuo-Sin, Mot-Pic Producer, The
Asia Pictures Ltd., 203 Princess Theatre

Bidg., Kowloon, Hong Kong, China. (M)

Chao, Eugene Yao-Chun, Recording Eng.,
U. S. Information Service, 187 Electric Rd.,
First Fl., Hong Kong, China. (M)

Chow, Raymond Ting-Hsing, Radio & Mot-Pic
Productions, U. S. Information Service.
Mail: 459 Sect. 4 Homuntin New Village,
Kowloon, Hong Kong, China. (M)

Cooper, Peter H., Production Mgr., U.P.A.
Pictures, Inc., 60 E. 56 St., New York. (A)

Corcoran, Laurence M., Studio Owner, Ser-
vicio Espanoles De Sonido S.A., Claudio
Coello 124, Madrid, Spain. (M)

Crane, Richard Warren, Supervisor of Color
Operations, CBS. Mail: 5 Hawthorne La.,
Valley Stream, N.Y. (A)

Craney, Ed B., Radio & TV, Net. Mail: Box
1956, Butte, Mont. (A)

Curwen, Ernest Charles, Supvr. Application
Eng. Lab., Sylvania Electric Products, Inc.
Mail: Box 21, S. San Gabriel, Calif. (M)

Davidson, James R., Photog., Free-Lance, 4708
Wedgewood, Bellaire, Tex. (M)

Dean, Curtis, Product Designer, Fairchild
Camera & Instrument Corp. Mail: 99-05
63 Dr., Rego Park 74, N.Y. (M)

Denham, Elmer Chester, Mot-Pic Lab. Techn.,
Cine-Graphic Film Lab., Inc., 1720 Olive St.,
St. Louis 3, Mo. (A)

Dudley, Winfield Harold, Supvr. Projection &
Sound, Stanley Warner Theatres, 6425

Hollywood Blvd., Hollywood. (A)

Easson, Alexander, Photog. Instrumentation
Engineer, Computing Devices of Canada,
Ltd., 4 Lake Ave., Carleton Pl, Ont, Can.
(M)

Elliott, Joe Wilson, Photog.-Cameraman, Free-
Lance, 612 N. Rossmore Ave., Hollywood 4.
(A)

Emmerson, George, Supvr. Photcg., Jet Propul-
sion Lab. Mail: 3012 Henrietta Ave., La
Crescenta, Calif. (A)

Ferrucci, Jack R., Univ. S. Calif. Mail: 1569
Glenville Dr., Los Angeles 35. (S)

Finestauri, Elio, Director of Lab., Stabilimento
S.P.E.S., Viale Campo Boario 57, Rome, Italy.
(A)

Florea, John, Cameraman, Free-Lance,
1080 Ravoli Dr., Pacific Palisades, Calif. (M)

Fornoles, Juan D., Chem. Eng., LVN Pictures,
In~., Quezon Citv, P.I. (A)

Foshaug, Martin Melvin, Mot-Pic Producer,
Jet Propulsion Lab., 254 Fillmore St. Pasadena
Calif. (A)

Fracker, Henry Edward, Sound Eng., Westrex
Sound Services, Inc., 1021 N. Seward St.,
Hollywood 38. (M)

Gabourie, Fred W., Chem. Eng., Motion
Picture Enterprise, Inc. Mail: 367 W. Spazier
Ave., Burbank, Calif. (M)

Gallez, Douglas Warren, Univ. S. Calif. Mail:
4617 Adenmoor Ave., Lakewood 8, Calif. (S)
Gaynor, Wardell, Cameraman, UPA Pictures,

Inc. Mail: 23 Hillside Ave., Newark, N.J. (A)

Gips, Robert E., Vice Pres. Production, Mel
Gold Productions, Inc., 1639 Broadway,
New York 19. (M)

Geldsmith, Walter D., Magnetic Recording
Applications Eng., Ampex Corp., 934 Charter
St., Redwood City, Calif. (M)

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December 1956 Journal of the SMPTE Volume 65 663 ee

why the ARRIFLEX 16
is the most desirable
professional 16mm camera

TRUE MIRROR REFLEX SHUTTER
Because of its — not a beam splitting device — passes 100% of the light

features to film and viewing system intermittently.

FINDER SHOWS BRIGHT IMAGE THROUGH TAKING LENS
— even in poor light. 10X magnification; no parallax; no
misframing; accurate, easy follow-focus.

REGISTRATION PIN IN PRECISION FILM GATE
) — with balanced rear pressure pad, side pressure rail, cross

stages around aperture. This means rock-steady pictures,
no film “breathing,” 35mm-like film quality.

THREE LENS DIVERGENT TURRET
— lets you use wide angle lens to 300mm telephoto without
physical or optical interference.

INSTANT-CHANGE LENS MOUNT
— with large-flange surface insures positive seating and
precise flange focus and alignment.

LARGEST CHOICE OF LENSES
— by famous makers. From 11.5mm extreme wide angle
to longest telephoto.

VARIABLE SPEED MOTOR

— electrically driven by light, compact, rechargeable bat-
teries. Motor instantly interchangeable for other types —
Governor Controlled, Synchronous and Animation.

TACHOMETER, FOOTAGE AND FRAME COUNTERS —

HAND-HELD FILMING

— all these features in a camera so light (only 6% Ibs), so
formfitting, with its ingenious Contour Hand Grip, that
steady, hand-held filming is easy.

664 December 1956 Journal of the SMPTE Volume 65

"Gan nm
—
&

Because of its __!t isa hand camera for newsreel and fast action filming

versatility It is a studio camera when you add the 400’ Magazine and the
Synchronous Motor.

It is a sound camera when you put it in the Arriflex Blimp.

It is also an animation camera, a scientific laboratory camera,
a medical camera, a cine-micrographic camera.

You can start with the hand camera, and as your requirements
demand, add the special purpose accessories, and yet be able to
convert it back to a hand camera in a few seconds — and with-
out the use of even a screwdriver.

Because it is Here is a precision camera that can “take a beating” and still

d d bl deliver the goods.
rugged anc re ° For instance: Al Milotte, ace Disney wild-life photographer,

shot over 90,000 feet for “African Lion” with one Arriflex 16,
in the rough tropics.

Disney cameramen found the Arriflex 16 most reliable during
the Navy North Pole Expedition in 1954.

Now eight Arriflex 16’s are at the South Pole with Disney.
Disney Studios has already purchased more than 30 Arriflex 16
cameras—so far.

Because of factory A modern, fully equipped service center is maintained in
service in the U:8. Nev, City. manned by factory trained technicians. A

complete stock of Arriflex parts is always on hand. Because
Arriflex owners derive their income through the use of their
cameras, service is handled on the promptest possible basis—
in most instances within 24 hours.

Because of its You cannot buy another registration-pin 16mm camera unless
you pay more than twice as much. If you “doctor up” an
reasonable price ordinary 16mm camera with accessories needed for professional
use, it will cost you more than the Arriflex and you still won’t
have a professional camera, not to talk about the many ex-
clusive Arriflex features.

ARRIFLEX 16, complete with
Variable Speed (wild) Motor,
Battery Cable, Neck Strap $162500

Matte Box and Lenses, additional

Sole U.S. Distributor
KLING PHOTO CORPORATION 750s tteiroce Avenue, Hollywood 46, 6
7303 Melrose Avenue, Hollywood 46, Cal.
Representatives in: Boston, Mass. Charlotte, N.C. Chicago, Ill. Denver, Colo. Detroit, Mich. Houston, Tex. Kansas City, Mo.
Hollywood, Cal. Memphis, Tenn. Miami, Fla. Newark, N.J. New York, N.Y. Philadelphia, Pa. San Francisco, Cal. Seattle, Wash.
Sold through authorized Arriflex Dealers.

December 1956 Journal of the SMPTE Volume 65

“4 ¥

Gorth, Philipp Wayne, Film Timer, Con-
solidated Film Industries. Mail: 11832 Dal-
wood Ave., Norwalk, Calif. (A)

Gundelach, Charles A., Cameraman-Produc-
tion, Free-Lance, 2311 Brewster Ave., Red-
wood City, Calif. (M)

Hanson, Everett Lyle, Foreman, General Film
Labs. Mail: 2242 Camden Ave., Los Angeles
64. (A)

Hart, Hal, Title Maker, Free-Lance, 4077
Beverly Blvd., Los Angeles 4. (A)

Heath, Donald Stevens, Univ. S. Calif. Mail:
Aeneas Hall, Los Angele. 7. (S)

Henry, Jon, Univ. Calif. L.A. Mail: 3914 Berry
Dr., Studio City, Calif. (S)

Ho, George Hoo-Chong, Senior Executive,
Manners Engineering Ltd., Box 235, Alex-
andra House, Hong Kong, China. (A)

Hoadley, Howard W., Manager, Mot-Pic &
Still Depts., Marquardt Aircraft Co. Mail:
9143 Petit Ave., Sepulveda, Calif. (A)

Hodgkins, Roger W., Radio & TV Eng.,
Guy Gannett Broadcasting Services. Mail:
RFD 2, S. Portland, Me. (M)

Hoffmann, Howard E., SRT TV _ Studios.
Mail: 3169 Waterbury Ave., New York. (S)
Holcomb, Arthur Lee, Associate Dir. Research,
Deafness Research Lab., 4570 Sunset Blvd.,

Los Angeles 27, (M)

Hu, King Chin-Chuan, Radio Program Prod.,
U. S. Information Service, 46B Kadoorie Ave.,
Kowloon, Hong Kong, China. (M)

Irish, George H., Mot-Pic Sound Recordist,
U. S. Government. Mail: 2725 Ordway St.,
N.W., Washington 8, D.C. (M)

Kalet, Donald, Chemist, Ace Film Labs. Mail:
1845 Ocean Ave., Brooklyn 30, N.Y. (A)

Kanamura, Riichi, Chief Eng. Sound Re-
cording Equip., Daiei Mot-Pic Kabus iki
Kaisha. Mail: Oogino-Machi, Hanazono,
Ukyo-Ku, Kyoto, Japan. (A)

ANO LITERATURE

Kay, Joseph E., Tech. Operations Supvr.,
National Broadcasting Co., Sunset & Vine,
Hollywood. (A)

Kell, Ray D., TV Eng., RCA Labs., 487 Jeffer-
son Rd., Princeton, N.J. (M)

Kellogg, George S., Instrument Designer,
Free-Lance, 2607 Evans Dr., Silver Spring,
Md. (M)

Kirkham, Robert Joseph, Lab. Technician,
U. S. Government. Mail: 2212 Woodberry
St., Hyattsville, Md. (M)

Kuperman, Howard, Film Editor, UPA Pic-
tures, Inc. Mail: 35 W. Eighth St., New York.
(A)

Kushner, Lawrence D., Photog., Rand Corp.
Mail: 605 S. Barrington, W. Los Angeles 49.
(A)

Laughridge, Tom Ovander, Mot-Pic Camera-
man, Lockheed Aircraft Corp., 1732 N.
Wilton Pl., Hollywood 28. (A)

Leung, Mathew P. W., Radio Techn., U.S.
Information Service. Mail: 10 Junction Rd.,
First Fl., Kowloon, Hong Kong, China. (M)

Long, Fang, Manufacturer, Taiwan Film
Studio, 14 S. Chungking Rd. Second Sect.,
Taipei, Taiwan, China. (M)

Lynch, Harold M., Cinematographer,
Technisonic Studios, Inc., 1714 Canary Cove,
Brentwood 17, Mo. (A)

Maurer, Leon Herbert, Tech. Dir., Illustrated
Films, Inc., 8460 Santa Monica Blvd., Holly-
wood 46. (M)

Maurer, Norman Albert, Producer, [Illustrated
Films, Inc., 8460 Santa Monica Blvd., Holly-
wood 46, (A)

Mayer, Bruce, Lab. Techn., Charter Oak
Telepictures, 846 Seventh Ave., New York.
(A)

McWilson, Roger C., Elect. Eng., General
Electric Co. Mail: 257 Granvil Dr., Louisville
18, Ky. (A)

Menville, Douglas Alver, Univ. So. Calif.
Mail: 3016 Shrine Pl., Los Angeles 7. (S)

Miller, Charles H., Photographer, Timer,
USAF, 4780 Burkhardt Ave., Dayton 3, Ohio.
(A)

Miller, Henry L., Radio & Mot-Pic Officer,
U.S. Information Service, Hong Kong, China.
(M)

Miltenburg, William Hubert, Chief Eng. &
Mer. Recording Dept., Radio Corp. of
America, Victor Div., 155 E. 24 St., New
York 10. (M)

Mitchell, Stanley John, Jr., Lab. Techn.,
Capital Film Labs., Inc. Mail: 518 Ninth St.,
N.E., Apt. 310, Washington 2, D.C. (M)

Miyamoto, Hirotsugu, Eng. Sound Equipment,
Westrex Co. Mail: 40, 3 chome Morita-cho
Nakamuraku, Nagoya, Japan. (A)

Mulholland, George C., Sound Eng., Canadian
Film Industries, Ltd. Mail: F11 Kingscourt
Apts., Ajax, Ont., Can. (A)

Nam, Lee Mong, Tech. Mgr. Film Studio,
Malay Film Productions, Ltd., 8 & 9 Jalan
Ampas, Singapore, Malaya. (A)

Neroda, Emil, Sound Eng., Reeves Sound
Studios. Mail: 1526 Brookside Dr., Union,
N.J. (M)

Niklewski, Martin Stanley, Mot-Pic Lab.
Techn., U.S. Government. Mail: 1307
Twelfth St., N.W., Apt. 402, Washington 5,
D.C. (M)

Odze, Meyer, City Coll. N.Y. Mail: 1765
Bathgate Ave., Bronx 57, N.Y. (S)

Pan, Sunny S. T., Correspondent, Pan-Asia
Newspaper Alliance, Printing House, 6
Duddell St., Hong Kong, China. (M)

Pfister, Robert Arthur, Chem. Eng., Cinerama,
Inc. Mail: 86 Baldwin Ave., Baldwin, N.Y.
(A)

Propper, Philip, Administrative Asst., Todd
AO Corp. Mail: 605 E. 82 St., New York. (A)

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December 1956 Journal of the SMPTE Volume 65

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Read, Keith E., Eng., Cinesound Co., & KCO?P.
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Roeth, Harold W., Antioch Coll. Mail: 209
Xenia Ave., Yellow Springs, Ohio (S)

Scott, Walter K., 3601 Wisconsin Ave., Washing-
ton, D.C. (A)

Sharpe, Donald Sidney, Film Inspector, Peerless
Film Processing Corp., 35 Christopher St.,
New York. (A)

Shaw, Vee-ing, Company Dir. & Mgr., Shaw
& Sons Ltd., 18 Dorset Crescent, Kowloon-
Tong, Hong Kong, China. (M)

Shiomi, Bunsaku, Chief Eng. Sound Recording

Equip., Nikkatsu Cinema Studio, 400, 4
chome Hyakunin-Cho Shinjuku, Tokyo,
Japan. (A)

Skot-Hansen, Mogens, Producer, Pres., Laterna
Film, 10 Sct. Jorgens Alle, Copenhagen V,
Denmark. (M)

Snazelle, Ernest Edward, TV Film Producer,
Free-Lance, 315 Sutter St., San Francisco, (M)

Sterling, D. L., Mot-Pic Editor, Northrop
Aircraft. Mail: 1258 W. Vernon Ave., Los
Angeles 37. (A)

Stratton, Charles Nelson, Mot-Pic Camera-
man, Panavision, Inc. Mail: 1024 Via Mirabel,
Box 903, Palos Verdes Estates, Calif. (A)

Terry, Leon Ronald, Eng., Canadian Broad-
casting Corp., Box 10, Snowdon, Montreal,
P.Q., Canada. (M)

Terry, John J., Sales Eng., Bell & Howell Co.,
7100 McCormick Rd., Chicago 45. (A)

Tong, Siu-Kee, Eng., Westrex Co., Asia, 401
Victory House, Wyndham St., Hong Kong,
China. (M)

Vides, Max Mejia, Cameraman & Editor,
Cinefoto Massi & Co. Mail: Juan Mora 57,
Col. C. R., San Salvador, C.A. (M)

Wilson, Oscar Cecil, Mgr., Canadian Broad-
casting Corp. Mail: 225 Indian Rd., Toronto,
Ont., Can. (M)

Wilson, Paul M., Lab. Techn., Eastman Kodak
Co. Mail: 2625 Purdue St., Los Angeles 64.
(A)

Wilson, Stanley S., Supvr. Video Operations,
Canadian Broadcasting Corp., 4539 Wilson
Ave., Montreal, P.Q., Can. (M)

Wyper, William Worthington, Mot-Pic Dept.,
North American Aviation, Inc. Mail: 3845
Gardenia Ave., Long Beach 7, Calif. (A)

Yaeger, Renee J., Assistant Lab. Mgr., Western
Cine Service. Mail: 3124 W. 20 Ave., Denver,
Colo. (A)

Yeh, Li, Managing Dir., Central Motion Picture
Corp., 150 Poh Ai Rd., Taipei, Taiwan, China.
(M)

Zaccaro, Neil, Broadcast Eng., WKNB, 104 N.
King St., Elmont, N. Y. (A)

Zugerman, Milton, Plant Manager, Color
Research Labs., 321 S. 12 St., Philadelphia 7
(M)

CHANGES IN GRADE

Bayless, Hugh, (S) to (A)
Fleischer, Eugene B. (S) to (A)
Gold, Leon Sigmund, (S) to (A)
LeGault, Joseph William, (S) to (M)
Mankofsky, Isidore, (S) to (A)
Moore, Russell Gordon, (A) to (M)
Morrison, James C., (S) to (A)
Muir, Duane Manson, (S) to (A)
Neumer, Jr., Arthur E., (A) to (M)
O’Rork, William M., (S) to (M)
Stockert, Henry A., (S) to (A)

DECEASED
George Burgess

Flat 6, 72 Notting Hill Gate, London W. 11,
England. (A)

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reviewed

Color Television Engineering

By John W. Wentworth, Published (1955)
by McGraw-Hill Book Co., Inc., 330 West
42 St., New York 36. 459 pp. Illus. Graphs.
6 X 9 in. Price $8.00.

This book has been prepared for engi-
neers who are familiar with basic television
principles and circuits: deflection, syn-
chronization, clipping, d-c restoration, etc.
The material is based on lecture notes over
the period 1950-1955, which fact has no
doubt contributed to the orderly arrange-
ment, freedom from errors, and noteworthy
clarity.

Part 1 is an excellent presentation of the
physical and psychological aspects of color,
and the measurement and specification of
color

Part 2, Principles of Color Reproduction,
includes useful background material on
photographic color methods, and a very

comprehensive discussion of transfer char-
acteristics.

Part 3, Principles of Color Television
Transmission Systems, contains some de-
tails of color transmission on the standard
6-mc television channel, and the makeup
of the NTSC color signal. Multiplexing
techniques used in the NTSC system are
described, and consideration is given to the
field, line, and dot sequential systems. His-
torical information is held to a minimum
consistent with clear explanation of the
broad concepts. This section might have
been expanded, and in parts would have
been strengthened by more specific design
detail.

Part 4, dealing with Apparatus and Cir-
cuits for color television ; is the book’s only
major weakness. The author, by and large,
emphasizes as “typical” the methods and
equipment of but a single manufacturer,
and minimizes contributions to the art by
others. On page 326, relative to flying-spot
scanners, it is stated “*. . . several companies
announced commercial models of color
television cameras based on this approach.”
As a matter of fact, there are three com-
panies that have commercial units of this
type available for sale; and there are a
number of color film scanner installations,
the first of which was put into regular
broadcast service in October 1954. Color
slide scanners were in regular use before
this. Live color scanners, admittedly a more
recent application (demonstrated before
NARTB in 1955) are not mentioned. Simi-
larly, certain types of display tubes and test
equipment which have been described in
the literature are not discussed. This sec-

3) 3-light color compensating head

for additive color printing
Speed to 125 ft. a minute
Fits Bell & Howell D or J pedestals in wo own shop

Also fits Depue-Carlson Step

Low Cost

Changes existing black-and-white to
additive color printing. 3-light addi-
tive color; discrete blue, green and red
beams. No one beam contributes to
contamination of the others.

Solenoid-operated, calibrated neutral
density glass filters. Five in each color
beam, giving 32 steps from 0.000 to
0.775 density in steps of .025 density.

Can also be used for step printing from
35 to 35mm. and 35 to 16mm., to fit a
Depue-Carlson printer.

High efficiency interference type di-
chroic beam splitters to form a single
mixed output beam.

A %-channel punched tape reader, with memo

rinter

Interchangeable parts @ Low upkeep

Colored glass and/or high efficiency
interference type trimming filters,
“peaked” to the positive stock sensi-
tivity.

Three 750-Watt bulbs, operating at
60-80 Volts. /.ssures long bulb life,
saving time in calibration.

Adjustable lamp sockets to line up fila-
ments. Three degrees of freedom—
vertical, rotational and lateral.
Four-leaf adjustable diaphragm, im-
aged at the printing aperture which
rovides an optical printing aperture
or exposure and/or uniformity con-
trol.

system reading in

succession red, green, blue, blank, is also available for actuating the

3 neutral density flipper assemblies descri

above, using as a

commercially available punched tape equipment for easy servicing.
Write us for further information
FISH-SCHURMAN CORP., 85 Portman Road, New Rochelle, N. Y.

December 19,6 Journal of the SMPTE

tion may have limited usefulness to an
engineer desiring to obtain complete in-
formation on available equipment and
circuitry.

The schematics and illustrations are
clear; the index is properly detailed, and
the references are relatively complete up
to January 1954. Of interest to this re-
viewer was Fig. 7-7, which may inadvert-
ently show some of the difficulties inherent
in the color printing process. The test
wedges were checked by 22 persons picked
at random, and in every case the observed
resolution of the color wedges was at least
twice that indicated for the ‘typical ob-
server.”

On the whole, Mr. Wentworth’s book is
extremely well done. It is a valuable con-
tribution to the literature and is recom-
mended for all who are concerned with
color television.—R. D. Chipp, Director of
Engineering, Allen B. Du Mont Labora-
tories, Inc., 35 Market St., East Paterson,
N.J.

Television and Radar Encyclo-
paedia, 2d ed.

Edited by W. MacLanachan. Published
(1954) by Pitman Publishing Corp., 2 West
45 St. New York 36. 216 pp. Illus.;
graphs. 5} X 84 in. Price $6.00

The editor and his contributors have
endeavored to compile, within the compact
space of 216 pp., a volume fitting its title.
It is amazing that they have done well,
though not perfectly, at this task.

It seems to this reviewer that the volume
is at its best where the subjects discussed are
covered at some length. For example, the
section covering the history of television in
Britain is well done and quite informative
to American readers. So is the article on
Central Control Rooms, that on Aerial
(Radar) and that on Outside Broadcast.
There is a good appendix, including mis-
cellaneous information such as details of
BBC television transmitters and a com-
parison table of world TV standards.

The faults of the book reside mostly in
the shorter definitions which it contains.
Some of these are misleading — for exam-
ple, frequency divider in television is “‘used
principally in the frame time base circuit in
which the series of eight frame synchroniz-
ing pulses are reduced to one by the cou-
pling from the sync separator circuit.”
Fortunately this definition concludes with
the words “See Integrator’! Also, the
wording is not always clear. In the section
on electron camera we are told that it has
“‘a grid consisting of a one-ended cylinder
with an aperture in the closed end.” To
one who is pedantic about his semantics,
this is a very difficult piece to make! A final
example, doubtful in respect of both
semantics and science, is the definition of
convex lens as “a lens which causes rays of
light to be separated and converge to a
point on a plane at the focal length of the
lens, on the side remote from the object
viewed.” The book would be much im-
proved by the omission of many of these
shorter definitions.

Since the book is published in England,
there is a natural tendency to emphasize
British terminology. There has been some
attempt to include American definitions,
not always necessary since many of the

Volume 65

ore

}
=
books
668

terms are used on both sides of the Atlantic.
Some unusual terms such as “Earthy”
(referring to the bypassed end of a tube
load circuit) and “Heart shape reception —
see Cardioid Diagram” were new to your
reviewer — perhaps they are to be regarded
as England’s answer to some quaint
American technical terms, such as “parc”
and “bootstrap”!

As a short technical reference in the fields
of television and radar, the book has much
to recommend it. It must therefore be for-
given for its shortcomings, in the hope that,
if its authors agree with these criticisms,
they may be corrected in a later edition.—
F. J. Bingley, Philco Corp., Tioga and C
Sts., Philadelphia 34.

Transistors I, RCA Laboratories.

Published (1956) by RCA Laboratories,
N.J. 676 pp. Illus. 6 X 9 in. Price $4.50.

Transistors I is a collection of 41 papers
by 39 authors on various aspects of the
transistor. These papers are the result of
research and development work at the RCA
Laboratories; ten of them have been pub-
lished previously. The papers cover a wide
range of transistor technology and are
divided into six sections: General, Ma-
terials and Techniques, Devices, Fluctua-
tion Noise, Text and Measurement Equip-
ment, and Applications. Abstracts of 46
additional papers resulting from RCA
transistor studies are appended. It should
be emphasized that Transistors I is not an
elementary text on transistors; it is a col-
lection of useful reference papers on the
subject.

The introductory or general section
of the book contains two review papers.
The first covers physical concepts of the
transistor, and the second describes some
state-of-the-art transistors, a few circuit
applications, and some additional physical
concepts. Both of these articles are inter-
esting reading for those not already famil-
iar with semiconductor devices.

The Materials and Techniques section
includes three articles on innovations in
germanium crystal processing, and six
articles related to fabrication techniques in
transistors. The paper on “Microscopic
Examination of Germanium Crystals and
Transistors” is a particularly interesting
and thorough treatment of the topic.
Generally, the Materials and Techniques
section will be of most interest to semicon-
ductor device engineers, and some of the
techniques described will be well known to
them. However, many engineers interested
in circuit applications of the transistor
would find this section useful in broaden-
ing their knowledge and understanding of
the transistor.

The Devices section describes the design,
construction and performance of new
germanium and silicon devices. The first
two papers concern improved emitter
efficiency at high currerts and improved
germanium power transistors. The third
paper describes a silicon alloy junction
transistor. The fourth paper describes the
design of a transistor with equal input and
output impedances for use in direct coupled
iterative circuits. The fifth and sixth papers
discuss improved high-frequency trans-
sistors, while the seventh and last paper of
the section covers a germanium junction

diode with voltage-variable capacitance
for use in UHF circuits. Most of the devices
described in this section are experimental
and not available as production items.
While semiconductor devices engineers
will find the Devices section well worth
reading, it has less value to the circuit
engineer.

Three papers comprise the Fluctuation
Noise section. The first paper discusses in
detail the noise power — inverse frequency
relation, or 1/f noise in diodes and transis-
tors. Two other papers cover noise repre-
sentation and measurements in junction
transistors. The effect of d-c bias on noise is
shown.

The test and Measurement Equipment
section provides detailed information on
high-frequency transistor test equipment,
and on testing transistors for power out-

put applications. This section will be very
useful to device engineers or circuit engi-
neers who are responsible for transistor
testing, and will be of general interest to
many others.

Almost half of Transistors I is devoted to
the circuit Applications section. The first
applications paper is a review of ambient
temperature effects on transistor operation.
Several bias stabilizing circuits are shown.
The next five papers discuss the use of
transistors in IF and RF circuits and in-
clude papers on an experimental automo-;
bile receiver and a developmental pocket
size broadcast receiver. The next three
papers cover power and audio amplifiers,
including complete circuit and performance
details of a 20-w transistor audio amplifier.
The audio amplifiers are followed by a
paper on amplitude and frequency modu-

Scratches on Film

Irritate Audiences

Scratches are havens for dirt, and
refract light improperly. On the
screen, they mar the picture and may
distract attention. If on the sound
track, they produce offensive crackling.

Fortunately, scratches can almost
always be removed — without loss
of light, density, color quality,
sound quality, or sharpness.

EERLESS

FILM PROCESSING CORPORATION
165 WEST 46th STREET, NEW YORK 36, N. Y.
959 SEWARD STREET, HOLLYWOOD 38, CALIF.

December 1956 Journal ofthe SMPTE Volume 65

iy
a
¢
669

lation of transistor oscillators. Then there
are three papers on transistorized television
receiver circuits, including sync separator,
vertical deflection and AFC circuits. Fi-
nally, there are three papers on transistor
switching and counting circuits. The
Applications section provides many prac-
tical ideas about transistor circuitry, and
gives the performance evaluation of a
number of experimental circuits. This
section should be very useful and interesting
to circuit engineers.

Following the Applications section there
dre 46 abstracts of-papers resulting from
RCA transistor work which were not
included elsewhere in the volume. These
abstracted papers also cover a wide range
of transistor technology from solid state
physics to transistor circuit applications.

Transistors I contains reference material
valuable to all phases of transistor work,
and it should be considered a worthwhile
addition to an engineer’s transistor library.
The book is not definitive on all the sub-
jects covered, but it does present a large
quantity of otherwise unpublished material
available within RCA. While the book does
not teach basic transistor electronics, it has
extensive supplemental value to those who
have an introductory knowledge of tran-
sistors.—W. V. Wright, Jr., Pacific Semi-
conductors, Inc., Culver City, Calif.

Transistors Handbook

By W. D. Bevitt. Pubiished (1956) by
Prentice-Hall, Inc., 70 Fifth Ave., New
York 11. 410 pp. Illus. 84 X 6 in. Price
$9.00

Transistors Handbook deals with the prac-
tical aspect of transistors and transistor
circuits. The first eleven of twenty-one
chapters describe transistor characteristics,
measurement techniques and circuit analy-
sis. The last ten chapters are devoted to
various kinds of transistor circuit applica-
tions and are largely comprised of specific
circuits. The book does not dwell on
physical concepts or detailed circuit
analyses of the transistor.

The chapter headings give an account of
the material covered: introduction, funda-
mental definitions and concepts, point con-
tact transistors, junction transistors, power
transistors, measurement of transistor char-
acteristics, methods of analysis of transis-
tors and transistor circuits, tetrode and
pentode transistors, photodiodes and photo-
transistors, some practical considerations in
transistor circuits, noise and temperature
effects in transistors, transistor audio and
power amplifiers, transistor R-F amplifiers,
audio oscillators, R-F oscillators, amplitude
modulation and detection, frequency mod-
ulation and detection, transistor radio and
television receivers, relaxation oscillators,
computer applications, and miscellaneous
applications. The appendix contains defi-
nitions of semiconductor terms (IRE
Standards, 1954), transistor manufacturers
and transistor characteristics.

There are two limitations to the useful-
ness of Transistors Handbook. First, almost
all of the material and references compiled
in the book ave dated 1953 or earlier. Many
transistors and transistor circuits repre-
sentative of current practice have been
developed since 1953; in fact, maturation
of the transistor industry really started in
the period 1954-6. Neither transistors

themselves nor transistor circuits are
“standardized” yet, and there will be many
useful innovations in transistors and cir-
cuits developed during the next several
years. Secondly, the very practical ap-
proach used in Tyansistors Handbook which
leans heavily on examples of early circuits
(pre-1954) does not give the basic design
steps of building a transistor circuit. The
circuit engineer will not find much assist-
ance in solving a current circuit design
problem.

While it is probably too early in the
rapidly growing transistor electronics field
to accumulate enough accepted and
standardized information for a true hand-
book, this book should be of considerable
use to many experimenters, technicians,
electronic servicemen, radio amateurs, etc.
The transistor circuit engineer will be
better served by current texts and reference
articles on transistors and transistor cir-
cuits.—W. V. Wright, Jr., Pacific Semi-
conductors, Inc., Culver City, Calif.

Die Kinematographische Kamera

By Dr.-Ing. Harald Weise. In German. Pub-
lished as Vol. III of a series entitled Die
Wissenschaftliche und Angewandte Photo-
graphie. Edited by Dr. Kurt Michel of
Aalen/Wuerttemberg, by the Springer
Verlag, Moelkerbastei 5, Vienna 1, Aus-
tria, 1955. 472 pp. 64 X 9§ in. 521 illus.,
schematic diagrams and photographs.
Available in the U.S. through Stechert-
Hafner, Inc., 31 East 10 St., New York 3.
Price $20.00.

As indicated in the editor’s preface of the
volume, the above work is part of a series
to replace and bring up to date the well-
known Handbuch der Wissenschafitlichen und
Angewandten Photographie by A. Hay and M.
von Rohr. The intent was to supersede this
almost classic work with a multi-volume,
encyclopedic reference series, each volume
of which would be a self-contained frag-
ment of the art, thus overcoming the
deficiencies of an all-encompassing single
handbook which can be up-dated only by
the unsatisfactory practice of issuing peri-
odic supplements. The present volume is in
the best tradition of its predecessors, com-
bining technical accuracy and painstaking
attention to detail with thorough coverage
of recent developments, including high-
speed photography.

Dr.-Ing. Harald Weise is the author,
among other works, of Kino Geraete Technik
which has previously been reviewed in the
November 1951 Journal). He has thus been
able to draw on an extensive experience
in the precision mechanism field in general,
and photographic apparatus in particular.
Die Kinematographische Kamera includes some
of the excellent illustrations of the earlier
work, while intentionally presenting the
present state of the art of camera construc-
tion from a more descriptive than an
analytical viewpoint. The extent of the
coverage of European and American
equipment is quite astonishing when one
considers that in many cases the author
cannot have had much more information at
his disposal than the sketchy sales literature
of the manufacturers. This observation held
true for Kino Geraete Technik, and holds true
now. In support of this consideration, the

reader’s attention is called to a bibliography
of 736 items from U.S., French and German
sources.

An effort has been made to present the
construction details of such mechanisms as
film drives, intermittent movements, shut-
ters, governors, optical systems, finders,
rangefinders, and coupled diaphragms in
an easily understandable and systematic
manner. To this end, families of devices
related by common operating principles
have been grouped, and certain historical
trends in the evolution of these devices
demonstrated. At the same time, the
author avoided the pitfall of letting the
presentation degenerate into a mere
cataloging of museum pieces. The work is
so profusely illustrated that, in the opinion
of the writer, little or no knowledge of
German would be required for the de-
signer and engineer to use it as a thesaurus
of camera mechanism. Though not ex-
plicitly stated, it is to be presumed that the
bulk of the ideas diagrammed belong to the
public domain, so that, in most cases, the
problem of patent infringement would not
exist. However, common caution in this
regard should not be ruled out.

Besides photographs and pictorial dia-
grams, the book contains analyses of cycles
kinematic and force diagrams, acceleration
graphs and equations, making it necessary
often to adapt only certain parameters and
physical dimensions to the designers’
specific problems, in order to obtain neat
solutions to what otherwise might be
tough nuts to crack. This is not to say that
the know-how of precision mechanism can
not be found with as great detail and often
with far more profound mathematical
treatment, in many texts of engineering
mechanics and kinematics. Rather, we
have here a selected concentration of those
mechanisms apt to be encountered in
camera design, and an impressive parade
of the way in which many men and many
manufacturers have solved problems which
seem to have a nasty habit of recurrin;
each time we set out to design a new piece
of camera equipment.

Among other things, the book covers
such topics as parallax characteristics of
viewfinders, blurring due to image mo-
tion and its parameters, constructional de-
tails of a representative number of objective
lenses, registration errors, et al. It has
always seemed regrettable to the writer
that there appear to be so few educational
courses in this country, where a young man
might train to become a photographic
engineer and camera designer. Certainly
the importance of photographic instru-
mentation to science and industry, to say
nothing of the military establishment,
would justify such a specialty. And yet the
predominant part of the requisite skills
must still be picked up on an on-the-job
apprenticeship basis in the engineering
departments of the companies in the field.
Perhaps an increase in the number of good
reference texts such as the present one, both
here as well as abroad, would help in
providing a much-needed impetus to the
further propagation of the photographic
art.—Peter V. Norden, Research
Laboratories, Poughkeepsie, N.Y.

670 December 1956 Journal ofthe SMPTE Volume 65

ty
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Products

Cand developments)

©6464 8 628 6 ae
Further information about these items can be
obtained direct from the addresses given. As in
the case of technical papers, the Society is not
responsible for manufacturers’ statements, and
publication of these items does not constitute
endorsement of the products or services.

We

The Tel-Animastand, a new Jow-cost ani-
mation stand that permits the production of
cartoons, titles and other special effects,
has been announced by S.O.S. Cinema
Supply Corp., 6331 Hollywood Blvd.,
Hollywood 28. A movable counter-balanced
vertical carriage which photographs the
artwork is designed to support the heaviest
of 16mm or 35mm cameras. Standard com-
ponents and interchangeable parts increase
the flexibility of the unit. The Add-A-Unit
or “‘building block” idea was adopted so
that the basic animation star'd may have
other equipment added to it.

Optical effects such as pans, angles,
zooms or quick close-ups are accomplished
by raising or lowering the camera. The
compound table can turn a full 360° as

well as travel to the front, back or either
side. All basic movements associated with
animation stands now used by the industry
are incorporated, Further information may
be obtained from the company at its Holly-
wood branch or from the New York head-
quarters at 602 W. 52 St., New York 19.

The Strong Super Trouper, a product of
the Strong Electric Corp., 87 City Park
Ave., Toledo 2, Ohio, is a high-intensity arc
spotlight with a self-contained power supply
unit consisting of a transformer and sele-
nium rectifier. It draws 10 amp from a
230-v single-phase line supply, or can also
be supplied for 110-v, 20-amp operation.
It is reported to equal or exceed in bril-
liancy of spot many large theater-type spot-
lights operating at a much higher amper-
age. The length of the spotlight house is 80
in., the base diameter is 28 in., and the ver-
tical tilt pivot is adjustable between 52 and
65 in. from the floor. The equipment, with
a net weight of 395 lb, is mounted on cas-
ters and is designed for ease of disassem-
bling into two units for shipment. Shipping
weight is 625 lb.

The Universal Camera Control System is
a simplified, light-weight, electronic camera
control system developed especially for air-
borne reconnaissance but applicable to
other uses. The Bill Jack Scientific Instru-
ment Co., Solana Beach, Calif., manufac-
tures this entirely automatic system. Input
data, such as ground speed, altitude above
terrain, terrain brightness, camera depres-
sion angle, lens focal length and film sensi-
tivity are fed to the system which computes
its answers continuously and rapidly by

The Bolex Underwater Case for photo-
graphic equipment used by skin divers is
designed for use at depths down to 330 ft.
It is designed to hold any Bolex H-16
camera locked into place with one lever,
without the use of tools or alterations of the
camera body. It is calibrated for any Kern
Paillard wide-angle lens — Switar 10mm
{/1.6; Switar 16mm //1.8; Yvar 16mm
{/2.8. The equipment is designed to be
operated from the outside while under
water with all essential controls provided
for — including winding, diaphragm set-
ting and shutter release. The footage coun-
ter is visible from the outside. Viewing is
done through a parallax-corrected gun-
sight located on the side of the case. Priced
at $600.00, it is available from Paillard
Products, Inc., 100 6th Ave., New York 13.

Hanimex (U.S.A.) Inc., distributors for
Durst copy cameras and color enlargers,
AK-16 motion-picture cameras and the
Siemens 2000 16mm projectors, has opened
a branch office at 770 11th Ave., New York.
The company’s main office is at 90 Steven-
son St., San Francisco. Operating as Hani-
mex (Pty) Ltd., the company maintains
offices at Sydney, Australia, Auckland,
N.Z., and a recently opened branch at
Tokyo, Japan.

DC analog methods. It operates for
types of aerial cameras, computing data on
how fast to move the film to equal the
velocity of the image, how much light to
let through the lens, how long to expose the
film and how often to take a picture so that
succeeding photographs will overlap uni-
formly. The building block system permits
replacement of each plug-in package with
an improved or miniaturized unit as soon
as it is developed.

672 December 1956 Journal of the SMPTE Volume 65

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INDUSTRIAL | EDUCATION | RELIGIOUS

bey

NOW! These six laboratories offer fast magnetic
Magna-Striping’ for all 16mm films!

Byron Labs
1226 Wisconsir. Ave., Washington, D.C.

Colburn Labs
164 N. Wacker Drive, Chicago 6, Illinois

Franchises

ward Street, Hollywo , California un
Nieuwe Gracht 7, Haarlem, Holland
Sathaporn Cinema Co.
2196 Tung Mahamek, Bangkok, Thailand FOR EVERY SOUND REASON

Reeves Soundcraft REEVES SOU NDCRAFT CORP.

|
671 Hope St., Springdale, Conn.
~ Sp 10 East 52nd Street, New York 22, N. Y.
December 1956 Journal of the SMPTE Volume 65 673

AS
/ - x

<YLAVALIER
Model 646 Dynamic

Remarkably small, versatile microphone—
for chest, desk or hand use. Frees hands
of announcer or performer for demon-

stration or dramatic effects. Recessed
screw in grille for adjustment of high
frequency response to suit the applica-
tion. No additional closely associated
auxiliary equipment required.

Peak-free respo

50 to 10,000 cps

Output —55 d)
Omnidirectional.
Acoustically treated
grille minimizes wind
and breath blasts. E-V
Acoustalloy diaphragm.
Available in 50, 150
or 250 ohms.
Non-reflecting gray
finish. Size: 1¥e” diam.
6%" long. Net wt:
6% oz. 30 ft. cable.
Supplied with neck
cord and support clips.
Mode! 646. List, $147.50.
Model 416 Desk Stand. List $5. <

Normal Trade
Discount Applies

Available from E-V Authorized Distributors
Write for Bulletin No. 120-V612

Elecho Voice

ELECTRO VOICE, INC. + BUCHANAN, MICH.

2

i

SLC

A closed-circuit system using an RCA
ITV-6 TV chain with a Perkin-Elmer
Auto-Zoom Lens enables students at the
University of Pennsylvania’s School of
Dentistry to peer, along with the instructor,
into the patient’s mouth. The instructor
speaks into a microphone hung around his

Matipo-Color Model C.C, 1956, is the
latest model film printer announced by
Andre Debrie Manufacturing Corp., 39 W.
32 St., New York 1. The machine was de-
signed especially to meet the requirements
of color and of large screens. It is presented
in four models, C.C.35; C.C.16; C.S.35;
and C.S.16. The first two models are
especially designed for pre-print materials,
monochrome separation positives, super-
imposed internegatives and reversal mas-
ters. The C.S. models are designed for pro-

neck, which leaves his hands free for han-
dling drills and other dental tools. The
Auto-Zoom Lens permits the students to see
the relative positions of patient, dentist and
equipment as well as close-up views of the
patient’s teeth.

duction printing. Brochures and mounted
examples of work on these printers are
available to show the printing and operat-
ing characteristics, products and accessory
equipment.

The new Guardian Exposure Meter is
shown including the attachment of the
Dynacell, an external cell which, when
added, is reported to increase the meter’s
sensitivity by 4 times for reflected light and
by 64 times for incident light. The General
Electric Company’s Guardian Meter has
been announced as designed to be twice as
sensitive as the firm’s older PR-1 exposure
meter. The new meter is reported to give a
useful reading with light so poor that with
film rated at ASA 100, an exposure of one
full second would be required with a dia-
phragm opening of {/5.6. Details are availa-
ble from General Electric dealers about
adjustments and adaptability of this direct-
reading meter for high ard low light values,
motion pictures, the Exposure Value System
and Polaroid uses. The new meter costs
$34.50; the Dynacell light cell, an addi-
tional $7.95; and the incident-light attach-
ment, $1.50.

674 December 1956 Journal of the SMPTE Volume 65

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The Super-Farron {/0.87 Lens has been
announced by the Farrand Optical Co.,
Bronx Blvd. and E. 238 St., New York 70,
as a well-correeted, high-speed objective
designed to assure effective results in
photographic and television applications

i even under the most unfavorable lighting
conditions. It is reported to cover a wide
field (30°) with a correction that holds up
over a broad spectrum.

In a 76mm focal length, the Super-
Farron covers a 40mm diameter field, and
is suitable as an objective for use with the
image-orthicon in TV cameras and for
35mm photography. In addition to the
standard infinity correction for direct
photography, the lens can be suppiied
corrected for 16:1 magnification for fluoro-
scopic application and corrected for 4:1
magnification for photography of oscillo-
scopes. It can be supplied for TV with
correction for the envelope thickness of the
pickup tube. Further technical and detailed
information can be found in Engineering
Report No. 327 available upon request
from the company.

The Neumade Shepard Electronic Film
Splicer has been announced by Neumade
Products Corp., 250 West 57th St., New
York 19. Exhibited at the SMPTE Con-
vention at Los Angeles, it is the result of
research to develop a method for splicing
not only older film stocks but also ‘‘Cro-
nar,” newly developed by E. I. du Pont de
Nemours & Co. Cronar cannot be satis-
factorily joined by the conventional splicing
methods. The new splicer has been de-
signed for CinemaScope and standard film
perforations. The splicing is described as
done electronically, using dielectric heating
to bond the ends. The splices are made
without cement or solution of any kind.
An overlap of 0.03 in. is produced.

processed
by
Movielab

MOVIELAB BLDG 619 W. 54th St.,N.Y.C. 19 yUdson 6-0360

December 1956 Journal ofthe SMPTE Volume 65 675

{
| = FILM LABORATORIES, INC. |

SPECTRA
Brightness Spot Meter

@ Checks
backing
rectly from camera position

uniformity of blue
for matte shots di-

@ Checks brightness of selected
areas on set to determine
brightness range

@ Checks color temperature of
light sources to maintain uni-
form color quality

@ Shows footcandle output of
individual light units without
interference from other sources

@ Measures uniformity of illum-
ination and discoloration of
projection screens for any dis-
tance or angle

®@ Maintains standard brightness
and COLOR TEMPERATURE of
printer lights

PHOTO RESEARCH CORP.

KARL FREUND, President
837 North Cahuenga Bivd.
Hollywood 38, Calif.

676

Secret Work Handled by Ansco Motion
Picture Processing Laboratories: An
ambiguity in an article in the September
Journal (p. 531) ‘nas been called to our
attention. The article stated that High-
speed Anscochrome 16mm motion-picture
film is now being sold without the cost of
processing included in the price of the film,
the reason being that government and
industrial users engaged in confidential
work would be enabled to maintain full
security by handling processing through
their own or selected laboratories. This is
correct. The article then states that for non-
confidential work Ansco maintains its two
processing laboratories at 2299 Vaux Hall
Road, Union, N.J. and 247-259 E, Ontario
St., Chicago, from which an inference may
be made that the laboratories do not
handle confidential or higher classified
work. This is incorrect. Confidential films
are processed in the Ansco Motion Picture
Processing Laboratories and the Union,
N.J., laboratory has security clearance for
all material up to and including “‘Secret.”’

or

A studio pedestal dolly designed to meet
the special requirements of a TV camera
mounting has been announced by W. Vin-
ten Ltd. of London. The equipment can be
tracked or crabbed as required by the move-
ment of a foot-controlled lever and is
mounted on three sets of double wheels.
The central column is supported on triple
hydraulic ram compensated by two com-
pressed nitrogen cylinders and a hydraulic
accumulator. This system allows prompt
head adjustment by lifting or lowering by
hand the pedestal head. Foot pedals are
provided which lock the central column in
any desired position. The three-draw cen-
tral column permits a height differential of
32 in. and a minimum height of 25 in.,
measured from the ground to the pedestal
head. The maximum height is 57 in. The
normal operating weight of the equipment
without a pan-and-tilt head is 430 lb. Ex-
port inquiries should be addressed to Cine-
matograph Export Ltd., 715 N. Circular Rd
London NW2, England.

The Mole Richardson Co.’s Catalog E
lists specialized lighting equipment for
motion-picture, still and TV _ studios.
The catalog also contains illumination
tables, power distribution data and other
information. lt can be obtained by writing
to the company at 937 N. Sycamore Ave.,
Hollywood 38.

employment
service

These notices are puolishea for the service of the
membership and the field. They cre inserted
three months, at no charge to the member. The
Society's address cannot be used for replies.

Positions Wanted

Administrative Engineer. The SMPTE’s Staff
Engineer, Henry Kogel, is seeking a new position,
after 6 years working with SMPTE Engineering
Committees and the motion-picture standards
program; also serving as Secy, American Stand-
ards Assn. Sec. Committee PH22, and Tech.
Secy, (nternational Standardization Orgn. Tech.
Com. 36, Cinematography; 2 years, previously,
develop. engr. with Sperry Gyroscope Co.;
B.S. Elec. Eng., Columbia Univ., 1948, after
military service as radio off.; age, 37; married;
N. Y. area pref. ; complete résumé upon request—
Henry Kogel, 19-24 202 St., Bayside 60, N. Y.;
Tel. BAyside 9-3574, or at SMPTE, LOngacre
5-0172.

Photographic Development Engineer. Free-
lance or consultation. Long experience in design,
development and production engineering of both
military and commercial motion-picture and still
cameras and projectors, enlargers, film editors,
lapsed time and sequence cameras, viewers,
automatic aperture controls, stereographic,
press cameras, etc. Military and commercial
references available on request. Write: P.O.
Box 601, Jamaica 31, N.Y.

Radio-Television Production or Directing
Assistant. January graduate Boston Univ.
(B.S. Communication Arts). Experienced AM-
FM-TV engineer (First Class Radio-Telephone
License). Radio production and _ directing
experience. Desire position with radio or TV
station specializing in live programming or with
TV film organization. Complete résumé on
request. Louis Maggi, 110 Lonsdale St.,
Dorchester 24, Mass.

Sound Recordist-Mixer-Editor. 18 years ex-
perience as broadcast and recording studio
technician, including 2} years variable area sound
film, double system. Moviola editing and cutting.
Formal musical education, read long score.
Transmission systems design, maintenance and
installation. Past 5 years as Technical Director
and Production Assistant for network package
producer with own facilities. Duties included
multiple tape re-recording and editing with re-
sponsibility for selection of b.g. music and effects.
Administrative. Highly specialized in “trick”
audio, producing over 1100 of these shows for
ABC-Radio. Some camera experience, own Cine
Special. Detailed résumé on request. 38 years old,
married, stable. Wm. Mahoney, 69 Tokeneke
Rd., Darien, Conn.

Positions Available

Television Film Director. Major department
head with proven record of administrative,
technical and leadership ability sought by WPIX,
New York, to supervise all film operations at
station. Man with outstanding qualifications will
be offered salary in five figures. Write full details
to: L. J. Pope, WPIX, Inc., 220 East 42d St.,
New York.

Top Sales Engineer for projection carbons.
Nationwide or territorial. Must have extensive
experience in the field and good contacts.
Write: Suite 3403, 70 Pine St., New York 5.

December 1956 Journal of the SMPTE Volume 65

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Professional

Services

PHOTOGRAPHIC
INSTRUMENTATION
Specializing in
HIGH-SPEED
Motion-Picture Photography

100 Rock

VIDEO FILM LABORATORIES
Complete Laboratory 16MM Service for
Producers Using Reversal Process
Also 16MM Negative and Positive Developing
Write for Price List
Video Film Labs are now located at
350 W. 50th St., New York 19. JUdson 6-7196

REVERSAL FILM CHEMICALS
for FILM and TV LABORATORIES

ATKINSON LABORATORY
7070 Santa Monica Blvd.
Hollywood 38, California

PROFESSIONAL MOTION PICTURE
PRODUCTION EQUIPMENT
Cameras, Sound Recording, Editing,
Laboratory and Affiliated Equip.
Consulting Services by Qualified Engineers
Domestic and Foreign
REEVES EQUIPMENT CORP.

10 E. 52nd St., NYC
Cable; REEVESQUIP

MITCHELL CAMERAS
16mm—35mm—70mm and accessories
for all applications
Studios—-Industry—Science— Research
CHARLES AUSTIN
Technical Representative
521 Fifth Ave., New York 17, N. Y. OX 7-0227

WILLIAM B. SNOW
Consulting Engineer
Acoustics—£lectronics
Stereophonic Recording
1011 Georgina Avenue
Santa Monica, California
EXbrook 4-8345

ROCKY MOUNTAIN HEADQUARTERS
For 16mm Film Services
Processing—Printing—Recording
Editing—Production—Renta!—-Sales
DuPont, Eastman and Fastax films in stock

Write for Price
WES SERVI INC.
114 E. 8th Ave., Denver 3, Colo. —%. 5-2812

CLASSIFIED ADVERTISING
First three lines $5.00
Each additional line $1.00
per inch $13.00

oD vou EVER SPOIL WORK because your lights

ELLIS W. D’ARCY & ASSOCIATES
Consulting and Development Eng
Xenon-Arc Applications
Motioa-Picture Projection
Magnetic Recording and Reproduction

Box 1103, Ogden Dunes, Gary, Ind.
Phone: Ogden Dunes 2451

FILM PRODUCTION EQUIP.
The world’s largest source of | supply for prac-
tically every need for
recording and editing ‘out picture films.

Domestic and Foreign
$.0.S. CINEMA SUPPLY CORP.

Dept. TE, 602 W. 52 St., N.Y.C.-Cable: SOSOUND
Western Branch: 6331 Holly’d Blvd., Holly'd, Cal.

FISCHER PHOTOGRAPHIC
LABORATORY, INC.
MErrimac 7-5316

1731 N. Mobile Ave., Chicago 39

FILM PRODUCTION EQUIPMENT
RENTALS SALES SERVICE

Cameras, Projectors, Recorders
Lighting, Editing, Lab. Equipment
Our Overseas Dept. Equipped for Fast
Foreign Deliver
Free Catalogs Available
FLORMAN & BABB
68 West 45th Street New York 36, New York
Cable. FLORBABB, New York MU 2-2928

16MM REVERSAL PROCESSING

ROUND-THE-CLOCK HI-SPEED
SERVICE OW TRI-x, DUPONT 930 4 931

Over four million feet of film successfully proc-
essed for TV, School and industry. Rate only

WE CONVERT AURICON CINE-VOICE
TO 400 FOOT MAGAZINE OPERATION

—Sioux Falls, S.

COLORTRAN CONVERTER
LIGHTING EQUIPMENT
The most illumination for the least investment
CROSS COUNTRY RENTAL SYSTEM
ELIMINATES COSTLY SHIPPING
write for catalog
NATURAL LIGHTING CORP.
612 W. Elk, Glendale 4, Calif.

CEMENT

WO MORE

pectedly? There is a simple, inex.
si dy—a stant voltage transformer
which you can afford. Drop us a postcard. M. R.
Company, Box 1220-FC, Beverly Hills, California.

16mm hi-speed Hills Filmatic
Pp inless steel, built-in replenisher
system, nitrogen gas agitati in lient condi-
tion, portable and self-contained. Valued excess
$7500. Can deliver i diately at tr d
discount Brochure on request. HAROLDS Motion
Picture Lab., Sioux Falls, S Dak.

OVERLAP

Model
“Deluxe Miracle”

Unaffected by humidity, same machine
functions for both regular or polyester base
photographic film without changeover.

Thermal Heating Not dielectric
No arc-over hazard No shock hazard
No FCC difficulties
No field service problem
Dark room splicing, a breeze!

The ONLY “BUTT-WELD” splicer that
satisfactorily splices CRONAR film.
* REG. E. |. OU PONT

Sample and Brochure on Request

te mirc PRESTO-SPLICER

“The finest film splicer, the
World over.”

Splices all types and sizes of
film including CRONAR* (Poly-
ester Photographic), negative,

print or optical—a film-fusion
(butt-weld) end-to-end.

DOUBLE CHECK THESE
BIG FEATURES:

scraping No cement
@No overlap @No lost picture
| @Automatically _pre-plasticized,

no drying out of splice

allin 2% seconds!

Time tested over 8 years, PRESTO-SEAL is

guaranteed to give perfect frame splicing on
35 or 16 mm film, with single thickness.

© Eliminates the need of AB printing
© magnetic track spliced without fall-outs
© no clicks going through projector
@ no edge oozing

PRESTOSEAL

3727 33rd st., Long Island City

December 1956 Journal of the SMPTE Volume 65

||
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677

remember...

only byron

can make
color-correct°

prints

e true fidelity color duplicates which
go far beyond mere coior balancing.

° negative-positive color processing
using EK 35mm and 16mm negative for 16mm release.

For information and price list,

write, phone or wire

byr on Studios and Laboratory

1226 Wisconsin Ave., N.W., Washington 7, D.C.
DUpont 7-1800

THE NATION’S DISCRIMINATING 16MM FILM PRODUCERS ARE CLIENTS OF BYRON
December 1956 Journal of the SMPTE Volume 65

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POSITION AND PLACED AT THE
BEGINNING OF THE FILM FOR
THE CONVENIENCE OF READERS

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remember. . .

only byr on
can make
color-correct®

prints

e true fidelity color duplicates which
go far beyond mere color balancing.

e negative-positive color processing

using EK 35mm and 16mm negative for 16mm release.

For information and price list,

write, phone or wire

byr on Studios and Laboratory

1226 Wisconsin Ave., N.W., Washington 7, D.C.
DUpont 7-1800

THE NATION’S DISCRIMINATING 16MM FILM PRODUCERS ARE CLIENTS OF BYRON
December 1956 Journal of the SMPTE Volume 65

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Contents — pages 658-678

Meeting Calendar

News Columns

81st Convention Program. .......+- 658
Education, Industry News .......+.--.+ 658
Color Television Engineering, by John W. Went-
worth, reviewed by R. D. Chipp; Television and
Radar Encyclopaedia, 2d ed., edited by W. Mac-

Advertisers

Camera Equipment Co... ....... + 667

Lanachan, reviewed by F. J. Bingley; Transistors
1, RCA Laboratories, published by RCA Labora-
tories, N.J., reviewed by W. V. Wright, Jr.;
Transistors Handbook, by W. D. Bevitt, reviewed
by W. V. Wright, Jr.; Die Kinematographische
Kamera, by Dr.-Ing. Harald Weise, reviewed
by Peter V. Norden.

Employment Service 676

Movielab Film Laboratories, Inc. . . .... . 675
Peerless Film Processing Corp. . . .....- 669
Precision Film Laboratories, Inc. . ..... 663
Prestoseal Mfg. Corp. . . + 677
Professional Services. . . . +++ +++ 677
Reeves Soundcraft Corp. . ....... 673

Symposium on Communication Theory and Antenna Design, spon-
sored by Air Force Cambridge Research Center and Boston Uni-
versity, Jan. 9-11, 1957, Boston University, Boston, Mass.

3rd National Symposium on Reliability and Quality Control in Elec-
tronics, Jan. 14-16, 1957, Hotel Statler, Washington, D. C.

American Institute of Electrical Engineers, Winter General Meeting,
Jan. 21-25, 1957, Hotel Statler, New York.

Audio Engineering Society, West Coast Convention, Feb. 7, 8, 1957,
Ambassador Hotel, Los Angeles.

National Photographic Show, Feb. 16-24, 1957, New York Coliseum,
New York.

Optical Society of America, Mar. 7-9, 1957, Statler Hotel, New York.

Radio Engineering Show and IRE National Convention, Mar. 18-21,
1957, New York Coliseum, New York.

American Physical Society, Mar. 21-23, 1957, U. of Pennsylvania,
Philadelphia, Pa.

International Photographic Exposition, Mar. 22-31, 1957, National
Guard Armory, Washington, D. C.

American Chemical Society, Apr. 7-12, 1957, Miami, Fla.

National Academy of Sciences, Apr. 22-24, 1957, Washington, D. C.

Symposium on the Role of Solid State Phenomena in Electric Circuits,

Polytechnic Institute of Brooklyn, Apr. 23-25, 1957, Engineering
Societies Building, New York.

American Physical Society, Apr. 25-27, 1957, Washington, D. C.

American Society for Testing Materials, June 16-21, 1957, Chalfonte-
Haddon Hall, Atlantic City, N. J.

American Institute of Electrical Engineers, Summer General Meeting,
June 24-28, 1957, Montreal, Que.

81st Semiannual Convention of the SMPTE, including Equipment
Exhibit, Apr. 29-May 3, 1957, Shoreham Hotel, Washington, D. C.

Western Electronic Show and Convention. \vg. 20-23, 1957, Cow
Palace, San Francisco

82nd Semiannual Convention of the SMPTE, including Equipment
Exhibit, Oct. 4-9, 1957, Philadelphia-Sheraton, Philadelphia.

83rd Semiannual Convention of the SMPTE, including Equipment
Exhibit, April 21-26, 1958, Ambassador Hotel, Los Angeles.

84th Semiannual Convention of the SMPTE, Oct. 20-24, 1958,
Sheraton-Cadillac, Detroit.

85th Semiannual Convention of the SMPTE, including International
Equipment Exhibit, May 4-8, 1959, Fontainebleau, Miami Beach.

86th Semiannual Convention of the SMPTE, including Equipment
Exhibit, Oct. 6-10, 1959, Statler, New York.

SMPTE Officers and Committees: The rosters of the Officers of the Society, its Sections
Subsections and Chapters, and of the Committee Chairmen and Members were published in the April 1956 Journal.

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Acme Film Laboratories, Inc.
Alexander Film Co.

Altec Companies

Animation Equipment Corp.
Ansco

C. S. Ashcraft Mfg. Co.
Audio Productions, Inc.
The Ballantyne Company
Bausch & Lomb Optical Co.
Bell & Howell Company
Berndt-Bach, Inc.
Bijou Amusement Company
Buensod-Stacey, Inc.
Burnett-Timken Research Laboratory
Byron, Inc.
CBS Television
Terrytoons, Inc.
The Calvin Company
Capital Film Laboratories, Inc.
Oscar F. Carlson Company
Century Lighting Corp.
Century Projector Corporation
Cineffects, Inc.
Cinema Engineering Company
Cinema-Tirage L. Maurice
Cine Products Supply Corporation
Geo. W. Colburn Laboratory, Inc.
Comprehensive Service Corporation
Consolidated Film Industries
Deluxe Laboratories, Inc.
Dominion Sound Equipments Limited
Du Art Laboratories, Inc.
E. |. du Pont de Nemours & Co., Inc.
Eastman Kodak Company
Elgeet Optical Company, Inc.
Max Factor & Co.
Fordel Films, Inc.
General Electric Company
General Film Laboratories Corporation
General Precision Equipment Corp.

Ampro Corporation

Askania Regulator Company

General Precision Laboratory Incorporated

The Hertner Electric Company
International Projector Corporation
J. E. McAuley Mfg. Co.

National Theatre Supply

The Strong Electric Company

W. J. Germas, Inc.

Guffanti Film Laboratories, Inc.
Hollywood Film Company

Houston Fearless

Hunt's Theatres

Hurley Screen Company, Inc.

The Jam Handy Organization, Inc.
Kalart Co.

sustaining of the Society
members

of Motion Picture

Kling Photo Corp. (ARR! Div.)
Kolimorgen Optical Corporation
Lorraine Carbons
Major Film Laboratories Corporation
J. A. Maurer, Inc.

Precision Film Laboratories, Inc.

Mecca Film Laboratories, Inc.
Mitchell Camera Corporation
Mole-Richardson Co.

Motiograph, Inc.

Motion Picture Association of America, Inc.
Allied Artists Products, Inc.
Columbia Pictures Corporation
Loew's Inc.

Paramount Pictures Corporation
Republic Pictures Corp.

RKO Radio Pictures, Inc.
Twentieth Century-Fox Film Corp.
United Artists Corporation
Universal Pictures Company, Inc.
Warner Bros. Pictures, Inc.

Motion Picture Printing Equipment Co.

Movielab Film Laboratories, Inc.

National Carbon Company, A Division of Union
Carbide and Carbon Corporation

National Cine Equipment, Inc.

National Screen Service Corporation

National Theaters Amusement Co., Inc.

Neighborhood Theatre, Inc.

Neumade Products Corp.

Northwest Sound Service, Inc.

Panavision Incorporated

Pathe Laboratories, Inc.

Polaroid Corporation

Producers Service Co.

Projection Optics Co., Inc.

Radiant Manufacturing Corporation

Radio Corporation of America

Reid H. Ray Film Industries, Inc.

Reeves Sound Studios, Inc.

Charles Ross, Inc.

$.0.S. Cinema Supply Corp.

SRT Television Studios

Shelly Films Limited (Canada)

The Stancil-Hoffman Corporation

Technicolor Motion Picture Corporation

Titra Film Laboratories, Inc.

Van Praag Productions

Alexander F. Victor Enterprises, Inc.

Victor Animatograph Corp.

Wenzel Projector Company

Westinghouse Electric Corporation

Westrex Corporation

Wilding Picture Productions, Inc.

Wollensak Optical Company

and Television Engineers

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